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           HOW TO DIAGNOSE, REPAIR AND UPGRADE YOUR
    AMPLIFONE AND WELLS-GARDNER COLOR VECTOR (XY) MONITORS
                    version 6.1 (4-6-96) by
              Gregg Woodcock (woodcock@nortel.com)

This article is Copyright worldwide 1991, 1996; all rights reserved.

OFFICIAL CYA LEGAL WARNING AND WAIVER:
Although I have made every effort to be precise, this article may
contain errors.  Even if it does not, some people may still damage their
machines or themselves while using the information found in this
document.  The author is neither responsible nor liable for any damage
or injury resulting from any use of this document.  The author makes no
guarantees of any kind; USE THIS INFORMATION AT YOUR OWN RISK.

COPYRIGHT INFORMATION:
I have gleaned a lot of the information included herein from copyrighted
materials released by various entities (a few are even included
virtually word for word).  The hardware we are discussing is "obsolete"
in the sense that it is no longer being made, sold, supplied or repaired
by Atari or Wells-Gardner.  I have talked to technicians in both
companies who, off the record, applauded my efforts and feel that their
respective employers couldn't care less about items this old and
"useless".  In that light, I see my inclusion of this information as
"fair use" (not in violation of the "spirit" of copyright law) in the
sense that this document may be the only way for many people to repair
their equipment.  I apologise in advance to Atari, Wells-Gardner,
Star*Tech Journal, and Play Meter for any perceived violation of the
"letter" of copyright law.  In sections where I have transcribed
documents word for word (indicated by a line of equals sign characters
"=" on the top and bottom), text inside square brackets ([]) is my
commentary and was not in the original article.

DISTRIBUTION RULES:
Reprint permission is conditionally granted to everyone.  For
publications, the conditions are that (1) I am to be notified before the
article is printed, (2) I must be credited and (3) I must be sent a copy
of the publication in which this article appears (customary free-lance
compensation would be greatly appreciated, too, but is not required).
Obviously, publishers/editors will need (and are granted) the right to
edit the text; I ask only that it be clearly indicated that the text was
abridged or altered (no specifics required).  Personal (private) use and
distribution is unconditional as long as the ENTIRE text is included
(additions are acceptable provided they are clearly marked as such).
Fair use applies for all; it is OK, to pull small sections of
appropriate text out to be given to people who need it without wasting
your time by crediting the source.

================================================================================

I'd like start off by thanking Rick Schieve (rls@intgp1.att.com) for
helping me get started in collecting and for donating a file which was
the seed for this document.

If this article does not suit your needs, there is probably more
technical information (which I have not seen) about vector monitors (of
all types) available from Star*Tech including a CD-ROM with 16 years of
articles on it!  You can contact them via email at startech@cybernet.net
or get them on the WWW at http://www.cybernet.net/web/startech/ or by
phone at 609/654-5544.

Before you ask, I do have a small cache of spare vector monitor parts
ranging from entire monitors, to individual PCBs, to discrete elements
(like the HV transformer) for both color and black-and-white units (no
Amplifone parts, though; sorry).  I am willing to sell or trade so just
send me some email or call me at 214.684.7380.  Also, please call me
before you junk any vector stuff; I hate talking with operators and
hearing, "I threw all that junk in the trash a few weeks/years ago!"  If
I can't get there to personally take it off your hands, I can make some
calls to friends around the world who will be able to.  There are quite
a few of us nuts who just love these old vector games.

Vector monitors, also referred to by Atari and others as "XY" (ick) or
"Quadrascan" (double ick) monitors, are available in black and white or
color.  A black and white picture tube has one electron gun that lights
just one type of phosphor (usually, but not always, white).  Color tubes
have 3 electron guns that, when the yoke and neck magnets are aligned
properly, each hit their own phosphors only, either red, green, or blue
(RGB).  Something called a shadow mask is used so each gun hits only one
set of phosphors.  There is no inherent difference between the tubes
used in vector monitors and the tubes used in raster monitors; only the
control circuitry differs.  That is not to say that you can use any tube
in any monitor; there are several different neck pinouts that have been
used for picture tubes so you have to find a tube with a matching pinout
first.  If you have a lot of screen burn, you can replace a color vector
picture tube with any compatible "off-the-shelf" 100 degree in-line
picture tube that is also used in raster-scan displays.

So far, this has been just basic TV stuff and it holds true for raster
monitors too.  Now we will diverge.  The electron guns in the neck of
the tube emit a stream of electrons that bombard the face of the tube
that would hit dead center if not for the deflection magnets on the neck
of the tube.  There are two deflection coils.  One for horizontal
deflection (X) and one for vertical deflection (Y) of the electron beam.
Consider the center of the screen to be (0,0) volts to the deflection
magnets.  If you want to move the beam to the right you put a positive
voltage on the horizontal deflection "X" coil (+,0).  A negative voltage
moves it to the left.  Up and down are accomplished with positive or
negative voltages to the vertical deflection (Y) coil.

The deflection coils are driven with the same kind of circuitry some
audio amplifiers use.  Imagine that the game puts out pre-amp analog
levels and that the monitor amplifies and displays the output.  There
are some vector monitors (the ones used in the Cinematronics games) that
are digital in nature and have a significantly different design.  Do not
assume that anything discussed in this document applies to these
monitors since much of it does not.

The third section is what (at least by Atari) is called the "Z"
amplifier which controls the brightness.  There is a "Z" amplifier for
each electron gun which means that black and white monitors have only
one "Z" amp and color monitors have three.

To draw an asteroid or other object the game shuts off the Z amp (or
amps) and applies the correct vector information to the X and Y
amplifiers driving the deflection coils to move the beam to the desired
location.  Then the appropriate Z amp(s) are turned on to illuminate the
screen and the vectors are modified to draw an outlined asteroid.  On
most monitors you can turn the brightness up to the point where the Z
amp(s) don't completely shut down and you can see the full path of the
electron beam as it flies around.  The designers of Star Wars exploited
these traces when laying out the dots for the starfield pattern and the
Death Star explosion to form "connect-the-dot" messages that say, "MAY
THE FORCE BE WITH YOU" on odd waves from 1 to 31 and, "HALLY MARGOLIN
RIVERA AVELLAR VICKERS DURFEY" (the last the names of the programmers
and other people involved with making the game) on even waves from 2 to
30 and on all waves from 32 to 99.

What I have described so far applies to all vector monitors.  Knowing
how these things work helps greatly in trouble-shooting.  For instance
deflection of the beam to the edges of the screen puts the greatest
strain on the X/Y deflection circuits so if you monitor has problems at
the edges, something is weak in that area.  The monitors make their own
positive and negative DC from AC inputs so a reasonable thing to check
would be the power supplies.  One of the main root causes of color
vector monitor problems is game lockups causing the monitor to go
extended periods with no input signal which fries it in short order.
The 2 main problems I have seen for game board lockups are bad solder
joints on the inter-board connectors (mainly Tempest) and also noisy
power supplies.  I suggest that you replace the power supply filter caps
with 105 degree Celsius capacitors instead of 85 degree ones; the higher
temperature caps last much longer and are more stable.

Vector monitors are also fussy about the quality of certain transistors.
The X and Y deflection circuits are very much like audio amplifiers and
tend to be hard on the big transistors used in the final stages of
amplification.  The Atari vectors use a push/pull rearrangement with NPN
and PNP transistors for both the horizontal and vertical amps.  If you
lose one of these transistors, you lose deflection in 1 of 4 directions
depending on which transistor goes out.

There is another circuit in the Atari stuff that is very important
called the spot killer.  What the spot killer does is shut down the Z
amp(s) if the X or Y circuits go bad enough to cause the beam to fail to
move around the screen enough to keep from burning the phosphors around
the zero axes.  The phosphors will become permanently damaged if the
beam stays in one place for too long.  When the spot killer is active a
red LED on the deflection board lights.  The spot killer also lights if
the logic board does not supply the low level X and Y signals for the
monitor to amplify or if the voltage supply for amplification is not
present so it does not always indicate a monitor failure.

Atari used 2 different (but pinout compatible) versions of the color
vector monitor.  The first and most unreliable was the Wells-Gardner.
The second (used only in Star Wars and dedicated Major Havoc machines as
far as I know) was the Amplifone.  There were several versions of the
Amplifone, early ones used in Quantum, and later ones used in Star Wars
have differing tube/yoke numbers.  I'm assuming they are all compatible
but don't know for certain?  Another quick aside; all the boards and
professionally produced documents spell the company name correctly as
"Amplifone" but lots of supplemental documentation (such as the document
below) misspell it as "Ampliphone".  I use whichever spelling was used
in the particular document presented.

Each monitor design has a slightly different electrical characteristic
and tube shape that will cause games designed for use with the Amplifone
to bulge out around the edges (a defect known as "barreling") when using
a Wells-Gardner and similarly will cause games designed for use with the
Wells-Gardner monitor to cleave inward around the outer edges (a defect
known as "pincushioning") when using an Amplifone.  It is quite minor
and is really only noticeable when in the self-test screen as this draws
a (perfectly straight) bounding box around the edge of the display which
makes it easy to notice.

The Amplifone uses a neck socket the same as most other (non-vector)
monitors from most other manufacturers use but the Wells-Gardner uses a
different socket.  The pinout, however, is the same so you just need to
convert them if you want to switch tubes between the 2 types.  If you
are careful, you should be able to pull off the plastic neck sockets
from the each tube as they are just glued on over the glass.  Then just
swap them.  For example, an Amplifone tube will work in a Wells-Gardner
chassis just fine (some versions of the Amplifone manual would lead you
to believe they won't but that mistake was corrected in later versions
of the manual) except that the display will bulge in the outer-middles
slightly.  This bulging is due to differences in the yokes and *might*
be counteracted by swapping the yokes (putting the Wells-Gardner yoke on
the transplanted Amplifone tube) but I haven't tried that yet.  If you
happen to run across a tube cross-reference chart, please let me know
what it says about RCA picture tube 19VLUP22 (the Wells-Gardner tube)
and Rauland tube M48AAWOOX (the Amplifone tube).

It is pretty easy to check to see if your tube is bad (it doesn't happen
a lot but it does happen).  Pins are counted counter-clockwise starting
at the gap (when looking at the backside of the tube).  Pins 9 and 10
are at either end of the heater element.  If you want to be absolutely
certain about which pin is which, check the socket on your neck board
(it should number all the pins).  The heater is basically a very low
wattage light bulb that emits the electrons which are shot at the
phosphor to make light.  You should read a short (OK, not a short but a
VERY low resistance) across pins 9 and 10 if your heater is OK.  If you
read an open, your tube is toast and there is nothing you can do (your
light bulb is burned out).  If your heater is OK, check to make sure
that the heater pins are not shorted to any of the emitter cathodes
(pins 6, 8, and 11).  If you see a short then your tube has a serious
problem but in many cases the short can be burned away.  Call your local
TV repair shop to see if they can "rejuvenate" it.

Here is the complete pinout of the neck/tube.
 1 - G3 (focus grid)
 2 - not used
 3 - not used
 4 - not used
 5 - G1 (control grid)
 6 - G (green cathode)
 7 - G2 (screen grid; brightness)
 8 - R (red cathode)
 9 - H (heater)
10 - H (heater)
11 - B (blue cathode)

Here is the complete pinout of the main connector (on the deflection board):
 1 - Red input (4.0V full on;  1.0V black level)
 2 - Green input (4.0V full on; 1.0V black level)
 3 - Blue input (4.0V full on; 1.0 black level)
 4 - Red GND (twisted pair with Red input)
 5 - Green GND (twisted pair with Green input)
 6 - Blue GND (twisted pair with Blue input)
 7 - X input (16V Peak-to-Peak; 2.5Kohms)
 8 - Y input (12V Peak-to-Peak; 2.5Kohms)
 9 - Not Used (Key)
10 - X GND (twisted pair with X input)
11 - Y GND (twisted pair with Y input)
12 - Power GND
13 - 25V RMS
14 - Power GND
15 - 25V RMS


SPECIAL NOTE:  The 2nd printing of TM-183 has a typo in Figure 8 on page
11 which incorrectly identifies the heater as existing on pins 5 and 6.
Strangely enough, both the 3rd and the 1st printings have the correct
numbers; go figure.

I should also mention that the monitor Sega used in it's vector games
(Electrohome's G08-CB0) is also an analog monitor and can be used in any
Atari vector game (and vice-versa) with the proper adaptors to mate the
different wiring harnesses (connectors) plus some circuitry to scale the
voltage ranges of the analog signals and the AC supply.  I do not have
documentation for the G08-CB0 so I cannot say exactly what scaling is
required but I can tell you that I have seen G08-CB0 monitors with
"Tempest" burned into them and I also saw a Wells-Gardner with "Space
Fury" burned into it.  I have talked to several people who claim to have
seen such a setup in action but they have no specifics.  I would
appreciate any details anybody can provide about the G08-CB0 and/or the
specific conversion details (either direction).

David Shuman <essayes@telerama.lm.com> had this to say about the
G08-CB0:  Sega XY monitors are analog monitors like the Atari XY's.
Unlike the Atari XY's, the Sega XY's don't have a "Z" channel.  The
connector from the game board to the monitor has only six connections:
R, G, B, X, Y, and GND.  The G08, unfortunately, is a thoroughly
screwed-up design.  The original G08 was apparently an operator's
nightmare, often consuming itself in flames.  Sega started shipping
revised monitors with some hacks added, presumably to improve
reliability.  The result didn't work too well either, and it looked
like Frankenstein's monster with parts hanging off everywhere, gobs of
glue, soldered connections where detachable connectors are required,
etc.  In the first two months I had my Eliminator, I had to fix the
monitor twice.  And since you can't disconnect the HV board from the
main board, you have to be very careful not to twist and yank out the
wires as you make your repairs.  Picking off factory-installed globs of
glue to access blown parts is no fun either.

I know this is supposed to be about Atari monitors but here is some
information the Sega color vector monitors that I found on page 12 of
the November 1981 issue of the Star*Tech journal.  I'll include it here
just in case you have one of those hybrid setups mentioned above.  If
anybody knows more about the redesign that is mentioned, please let me
know!

================================================================================

"SPACE FURY" COLOR (G-80) X-Y SYSTEM REDESIGN

Gremlin/Sega reports that all of the problems encountered with the
industry's first color X-Y game "Space Fury" have been identified and
solved [yeah, right].

The problems are centered around [ack, bad puns, too!]  the deflection
(X-Y) amps.  Underrated power transistors combined with an extended "on"
time during the power-up routine resulted in damaging the amplifier
circuit.

The remedy includes a modification to the card cage and replacement of
the Electrohome Monitor with a redesigned unit.

Gremlin/Sega will have replaced all defective monitors and modified all
game card cages by the end of October.

Initial field fixes did not resolve the problem entirely and
Gremlin/Sega decided to undertake the monitor replacement program.

Electrohome, the monitor manufacturer, will replace monitors in the
Eastern U.S., while Gremlin/Sega will handle the Western U.S.

For further details contact your distributor.

================================================================================

The Amplifone was commissioned as a replacement to the infamous,
failure-prone Wells-Gardner.  Unfortunately it had a horrendously
unreliable Achilles' heel; the HV transformer.  This part is widely (but
falsely) believed to be impossible to replace because there are no more
HV transformers around.  Fortunately, this is incorrect and they are
readily available, even though they are a bit expensive.

NOTE:  [Ob-anally-retentive-pet-peeve] This part is commonly but
improperly referred to as the "flyback" transformer.  This is a misnomer
because the flyback transformer exists only in raster monitors'
deflection circuits.  Part of a flyback's duty is to regulate the
currents necessary to make the electron beam "fly back" to the left (or
top) during retraces.  In vector monitors, the high voltage transformer
is a "flyback" transformer in the sense that it is constructed and
designed just like the flyback transformer in a raster monitor with the
exception that the flyback portion (the horizontal deflection coil) is
not needed and so is not present.  There is an oscillator circuit that
serves the purpose that the horizontal oscillator would in a raster
monitor, and there is a power transistor that would be called a
horizontal output transistor if it were in a raster monitor, but the
part of the transformer that controls the retrace (flyback) is not
present so there is no true flyback transformer in a vector monitor.  If
you must give it a name, use "HV" or "horizontal driver" instead of
"flyback".

As soon as Atari heard about all the failures of the HV transformers,
they commissioned a third party to supply them with a ton of
replacements for the Amplifone monitors since they were so unreliable
and in such high demand.  Unfortunately (for Atari), by the time they
were manufactured, nobody cared anymore (because the games that used the
Amplifone were getting old and starting to be retired/converted anyway
or else they had Wells-Gardner retrofits in them) so this fact is not
widely known to most people in the industry.

The replacement HV transformer was over-engineered to the max so that it
would not fail as much as the original part and to date Atari reports
that THEY HAVE NOT HAD EVEN ONE REPORT OF THE REPLACEMENT EVER FAILING!
To be critical, this could be due to the fact that by the time the
replacements became available, most people were no longer routing their
Star Wars machines (or at least not with the Amplifone monitors in
them).  Any machines being repaired and used today are likely to get
gentle home use which naturally lengthens the life of the monitor and
its parts.

If your HV is dead then it is probably either resistor R12 near the HV
transformer or the HV transformer itself.  CHECK THE RESISTOR FIRST
since it is much easier and cheaper to replace.  Simply unsolder it and
see if it has the proper resistance (2.2K Ohms).

The catch is that Atari replacement parts are only supplied at the
wholesale level to official Atari game distributors.  To find out the
distributor closest to you so that you can order this part from them,
call Atari at 408.434.3700 and give them you Zip or Area Code and they
will give you a business name and phone number.  I am pretty sure the
MSRP is about $160 but that is significantly cheaper than buying a
Wells-Gardner retrofit that you will have to repair about once a year
(most distributors discount such old parts below the MSRP so you
shouldn't have to pay that much especially if you comparison shop and
play the distributors off each other).

Starting with some information I provided to get him started, Tim Tewalt
<tewalt@peaks.ENET.dec.com> in mid-1995 attempted to bypass Atari and
the distributors by buying factory direct.  Here is what he discovered:

================================================================================

Hi guys; bad news.  The bottom line is $150 each when ordering a total
of 25 flybacks.  As Gregg Woodcock pointed out, Penn Trans of Wingate
PA, is no longer in business; hell, there's no such thing as Wingate,
PA, either for that matter.  I called the Postmaster in Bellefonte, PA
and found that Wingate was swallowed up by Bellefonte and more
importantly, Penn Trans was bought out by Wintron Inc.  The part number
926862802 from my flyback, matches the Wintron flyback part number, so I
was pretty sure I had found the source.  They faxed me a quote a few
days later with a price of $173.13 each on a quantity of ten and $149.83
each on a quantity of twenty-five.  *NOT* the deal I was looking for.
So anyway, I have decided not to pursue this any further.  If someone
else would like to look into this, you'll find some pertinent
information below.  Thanks a lot for your interest, guys.  Sorry I
wasn't able to come through.

"Flyback" Transformer for Amplifone XY monitor
   Atari part number: A201005-01
   Type number: 926862802 ("Transformer Multiplier")
   Manufactured by: 
       WinTron Technologies.
       276 Spearing Street
       Howard, PA 16841

       Phone: ... (814) 625-2720
       Fax: ..... (814) 625-2725
       Toll Free: (800) 865-5351
       Website:   http://www.wintrontech.com

[NOTE:  The reason for the high prices is that they do not have any
stock on hand and would have to retool the machinery to manufacture a
fresh batch.  Perhaps it would be simpler and cheaper to get the spec
from them and find out what it would cost to have a professional wire
one up by hand...]

================================================================================

If your HV transformer is dead then you will need to order Atari part
number A201005-01.  This part was available in inexhaustible quantities
from Atari until recently but now Atari claims they have no more.  I
suspect that with all the reorganizations of the company some of the
"dead weight" inventory was liquidated or thrown out altogether.  If you
make enough phone calls to large distributors, you should be able to
locate one.  If you do, please let me know and I'll add the information
to this document.  One person reported that when his HV transformer went
bad it took VR1, R20, and CR5 with it so you may want to test/replace
these parts, too (they are commonly available).

Here is the document that describes how to install an Amplifone HV
transformer.  Thanks to Keith Jarett (keith@tcs.com) for mailing me a
photocopy (who in turn wishes to thank Mark Sherman and Al Vernon of
Atari Games for their fabulous in-depth knowledge and tech support.  I
agree; these guys have helped me a few times, too, and are fantastic).

================================================================================

[NOTE:  To my knowledge, Atari never bothered to copyright these
instructions and they are not marked with a copyright symbol.]

     INSTALLING THE NEW AMPLIPHONE [sic] HIGH VOLTAGE TRANSFORMER
     ------------------------------------------------------------

1. Remove the defective flyback from the highvoltage [sic] P.C.B.
   [NOTE:  The new transformer has a black case and it is smaller than
   the original which has a red case]

2. Change R12 to a 1K ohm [1/4 Watt] resistor.  [NOTE:  recommended for
   durability; not strictly required]

3. Secure the new flyback to the high voltage pcb using the mount hole,
   tighten nut on the circuit side of the High Voltage P.C.B.  [NOTE:
   It bolts through the PCB, though you will have to first:
     - enlarge the through hole slightly
     - connect the wires from the transformer to the PCB
     - tape over the PCB to insulate the traces from the metal bottom
       of the transformer]

4. Solder the thick BLACK wire from the HV transformer to the TOP
   connector on the Focus block.

5. Feed all six color coded wires from the bottom of the HV transformer
   through the 2nd hole to the circuit side of the high voltage pcb.

6. a. Solder GRAY wire to the point labeled Filament. (see picture below)
      [NOTE:  This is where the "extra" wire from the old flyback went.]
   b. Solder ORANGE wire to [former] pin 1.
      [NOTE:  The photocopy I got with my replacement had the label for
      this pin cut off!  It is the pin that goes to the case of Q3.]
   c. Solder GREEN wire to [former] pin 4.
   d. Solder BLACK wire to [former] pins 6 & 7.
   e. Solder YELLOW wire to [former] pin 8.
   f. Solder RED wire to [former] pin 9.
   [NOTE:  Pin numbers are shown on the white plastic bottom of the old
   transformer and on the schematic if you have one; for this reason, I
   will not attempt to draw in the picture mentioned in (a)]

[A picture showing a full scale drawing of the solder side of the HV
PCB, has been omitted for obvious reasons.  It does not show anything
that cannot be derived from the included text; it was merely a "visual
aid".]

[NOTE:  End of document; here is further advice from the Atari techs...]

After you finish, you will need to adjust brightness (bottom pot on the
white module).  Use the self test screen for this.  Also adjust focus.
If nothing happens, the other (lower) focus wire is broken like mine was
[NOTE:  Mine was broken, too!].  Take off the rubber cap to verify.
Focus is the top pot on the white module.  This connection is fragile
and takes a lot of heat/current so it frequently breaks off.

Adjust R7 (the frequency of the primary switching) to get a video B+ of
180 volts.  According to Mark, this will give the correct HV.  You don't
really need to tweak R17 as described in the manual if you know that
your overvoltage protection cutoff is working OK.  Recheck focus after
tweaking R7.

If any problems occur, verify that the +24 and -24 volt regulators are
reasonably close to the correct output voltages.  Some departure is OK
if you have the 5 watt resistors bridging their inputs and outputs
(these are present to relieve the load under transient conditions such
as the all-white death star explosion).

The board should now run MUCH cooler.  I can comfortably touch all the
HV heat sinks which was not true before.

================================================================================

One word of caution about replacing the HV transistor (note that I said
"transistor", *NOT* "transformer"; we are shifting gears); double check
the part that you receive BEFORE you install it.  Why?  Here is a
transcription of a note I found tucked in a Star Wars manual which also
mentions how to tell if your HV transformer is (probably) bad, where to
mount a fan to lengthen its life, and a possible way to tell if your
tube is bad.  I have no idea where it came from:

================================================================================

ATARI STAR WARS HIGH-VOLTAGE BOARD
by Avery Petty
   A.P. Engineering
   Huntington Beach, CA

Recently, I repaired a whole fleet of Atari STAR WARS.  I sent someone
to the distributor to get the 'hard-to-find' high voltage transistor
BU406D [NOTE:  The transistor he is talking about Q3 labeled as "NPN
7-Amp.  400V Power Transistor" in the manual's parts list.].  He came
back with a BU406, no "D".  The "D" must appear on the transistor.  It
means there is a high voltage diode in the package.  So beware, even the
distributor can goof!

What will it cost you?  Your game maybe.  Without the diode, using the
BU406, the high voltage will work for awhile [sic], but will burn up the
flyback transformer which cost [sic] $90.00 [NOTE:  *much* more than
that now]!

If you are repairing a High Voltage board, and after replacing all the
capacitors, the two 24 volt regulators, and related parts and the high
voltage transistor with a BU406D, and you still don't have high voltage,
and don't know why, you can be sure it's your flyback transformer.  If
in doubt, pull it out and put it in a working STAR WARS and see, it will
only take 5 minutes [NOTE:  this is a severe under-estimate; I'd say it
is at least a 15 minute job not including swapping them back if that
needs to be done, but then again he is a professional and I am just a
hack :>].

When you finally fix it, put a fan under the board -mounted [sic] on the
wood rail the board is mounted on, blowing on the High Voltage board.
This is something that should be done to all STAR WARS, because the
flyback is the most expensive part there [NOTE:  advice to be heeded for
all Atari color vector games].

If your high voltage won't get up to at least 19,000 volts, you may have
a bad tube.  Look for real [sic] bad phosphor burn or a color missing.

================================================================================

Here is some text from the Major Havoc conversion kit installation
instructions (TM-268).  It describes the Atari sanctioned upgrade and
includes instructions for converting the Amplifone Deflection Board PCB
to the "official" upgrade.  Thanks to Tony Jones (ant@palm.cray.com) for
sending this to me.

================================================================================

[NOTE:  Atari did copyright these documents and they are clearly marked
with a copyright symbol.]

Major Havoc Installation Instructions TM-268

I. MODIFY THE AMPLIFONE DEFLECTION PCB
--------------------------------------

          +------------------------ NOTE ------------------------+
          | The following procedure applies to those Space Duel, |
          | Gravitar, and Black Widow games that used an         |
          | Amplifone display.  If your game has a Wells-Gardner |
          | display, perform "H. Modify the Wells-Gardner        |
          | Deflection PCB" [found later in this document].      |
          +------------------------------------------------------+

Perform the following procedure to modify the Amplifone Deflection PCB
(see Figure 8).

   1.  Set the Deflection PCB on a clean work surface.
   2.  Connect two type-1N754A Zener diodes together, anode to anode,
       as shown in Figure 6 [found later in this document].  Use a
       soldering iron to solder the two anode leads together.
   3.  Connect two type-1N756A Zener diodes together and solder as
       described in step 2.
   4.  On the component side of the Deflection PCB, locate the yellow
       wire connected to resistor R1 (left center of the PCB).
   5.  Solder one cathode lead of the two type-1N754A Zener diodes
       (soldered together in step 2) to the yellow wire on the soldered
       side of the Deflection PCB as shown in Figure 8.
   6.  Solder the other cathode lead of the two type-1N754A Zener diodes
       to the nearest ground on the PCB as shown in Figure 8.
   7.  On the component side of the Deflection PCB, locate the orange
       wire connected to Resistor R24 (right center of the PCB).

[Figure 8, entitled "Modifying the Amplifone Deflection PCB", showing a
full scale picture of the solder side of the Deflection PCB, has been
omitted for obvious reasons.  It does not show anything that cannot be
derived from the included text; it was merely a "visual aid".]

   8.  Solder one cathode lead of the two type-1N756A Zener diodes
       (soldered together in step 3) to the orange wire on the soldered
       side of the PCB as shown in Figure 8.
   9.  Solder the other cathode lead of the two type-1N756A Zener
       diodes to the nearest ground on the PCB as shown in Figure 8.
  10.  On the soldered side of the Deflection PCB, solder the cathode
       lead of a type-1N4002 diode to the emitter of transistor Q17 as
       shown in Figure 8.
  11.  Scrape away the green protective coating at a convenient point on
       the PCB, and solder the anode lead of the type-1N4002 diode to
       the collector of transistor Q17 as shown in Figure 8.
  12.  On the soldered side of the Deflection PCB, solder the anode lead
       of a type-1N4002 diode to the emitter of transistor Q16 as shown
       in Figure 8.  [NOTE:  This is the opposite of what you did in
       step 10.]
  13.  Scrape away the green protective coating at a convenient point on
       the PCB, and solder the cathode lead of the type-1N4002 diode to
       the collector of transistor Q16 as shown in Figure 8.
  14.  On the soldered side of the Deflection PCB, solder the cathode
       lead of a type-1N4002 diode to the emitter of transistor Q7 as
       shown in Figure 8.  [NOTE:  This is the opposite of what you did
       in step 12.]
  15.  Scrape away the green protective coating at a convenient point on
       the PCB, and solder the anode lead of the type-1N4002 diode to
       the collector of transistor Q7 as shown in Figure 8.
  16.  On the soldered side of the Deflection PCB, solder the anode lead
       of a type-1N4002 diode to the emitter of transistor Q6 as shown
       in Figure 8.  [NOTE:  This is the opposite of what you did in
       step 14.]
  17.  Scrape away the green protective coating at a convenient point on
       the PCB, and solder the cathode lead of the type-1N4002 diode to
       the collector of transistor Q6 as shown in Figure 8.

================================================================================

Here is an Atari Field Service bulletin courtesy of Al Kossow
(aek@haxrus.apple.com) which describes modifications to the Amplifone
monitor to make it more robust.  All the diagnostic/repair stuff is new
and compatible but the rest seems to be similar to part of the previous
Major Havoc documentation upgrade but they do differ in some respects.
I would advise that you only implement 1 of them unless you are sure
they are compatible (I am not).  If anybody knows if any are compatible
(or not), let me know.  For now, I am listing them as
mutually-exclusive; mix at your own risk.  I'd take the time and hassle
to do the first one even though it is a lot more work.

================================================================================

[NOTE:  To my knowledge, Atari never bothered to copyright these field
service bulletins and they are not marked with a copyright symbol.]

TECH TIP from the ATARI FIELD SERVICE DEPARTMENT

STAR WARS *

Atari Color X-Y Display Deflection PCB

You should do the following modifications to help prevent the Deflection
PCB from failing.  THIS MODIFICATION SHOULD ONLY BE PERFORMED BY A
QUALIFIED TECHNICIAN.

Parts List
----------------------------------------------------
Quantity   Description                    Part No.
----------------------------------------------------
   6       Type-1N4002 Diode              31-1N4002
   2       Type-1N754A 6.8V Zener Diode   131002-001
   2       Type-1N756A 8.2V Zener Diode   32-1N756A
   2       12 Ohm 5% 1/4 W resistor       110000-120

   1.  Connect the two 1N754A Zener diodes together as shown in Figure
       1.  The connection is made as follows:  bend the anode ends of
       both diodes into a "fish-hook" pattern.  Hook the two fish-hooked
       leads together, and solder them.  Remember that too much heat
       will destroy the semiconductor material.
   2.  Connect the two 1N756A Zener diodes together as shown in Figure
       1.  Use the same technique as described in Step 1 above.
   3.  Remove diode CR2 and solder in a type-1N4002 diode in its place.
       [NOTE:  On older monitors, CR2 is labeled D602.]
   4.  Remove diode CR11 and solder in a type-1N4002 diode in its place.
       [NOTE:  On older monitors, CR11 is labeled D702.]
   5.  Remove resistor R12 and solder in a 12 Ohm, 1/4W resistor in its
       place.  [NOTE:  On older monitors, R12 is labeled R609.]
   6.  Remove resistor R35 and solder in a 12 Ohm, 1/4W resistor in its
       place.  [NOTE:  On older monitors, R35 is labeled R709.]
   7.  Find the Y-Deflection Circuit (upper left area of the schematic).
       Resistor R1 has two leads to it.  Find the lead that goes to the
       yellow wire.  Connect this lead to the cathode of one of the
       type-1N754A diodes.  Connect the cathode of the other type-1N754A
       diode to ground.
   8.  Find resistor R24.  It has two leads:  one runs to an orange
       wire.  Connect this lead to the cathode of one of the type-1N756A
       diodes.  Connect the cathode of the other type-1N756A diode to
       ground.
   9.  Find the type-2N3792 transistor Q17.  You will be installing a
       type-1N4002 diode across the transistor's emitter and collector.
       Solder the cathode lead of the type-1N4002 diode to the emitter,
       and solder the anode to the collector of this transistor.
  10.  Find the type-2N3617 transistor designated Q16.  You will be
       installing a type-1N4002 diode across the transistor's emitter
       and collector.  Solder the cathode lead of the type-1N4002 diode
       to the collector, and solder the anode to the emitter of this
       transistor.  [NOTE:  this is the opposite of what you did in Step
       9.]
  11.  Find the type-2N3792 transistor Q7.  You will be installing a
       type-1N4002 diode across the transistor's emitter and collector.
       Solder the cathode lead of the type-1N4002 diode to the emitter,
       and solder the anode to the collector of this transistor.
  12.  Find the type-2N3716 transistor Q6.  You will be installing a
       type-1N4002 diode across this transistor's emitter and collector.
       Solder the cathode lead of the type-1N4002 diode to the collector
       and solder the anode to the emitter of this transistor.  [NOTE:
       this is the opposite of what you did in Step 11.]


CATHODE +-+------+        +------+-+ CATHODE
--------+ |1N75#A+--------+1N75#A| +--------     Diode Connection
        +-+------+ ANODES +------+-+

FIGURE 1 Making Fish-Hook Connections

[You get the idea; snub diodes across the deflection amps, back to back
Zeners on the input to ground.  Since I made these modifications, I
haven't had a deflection amp go out (but I'm running the game with the
back off now, too.)]

...

STAR WARS Vector-Generator PCB

Shaky Video
   Problem:  Some games may have shaky video after a 15-minute warm-up.
The video will start to shake in the high-score screen.  The words
PRINCESS LEIA'S REBEL FORCE will start to flutter and then worsen to an
up-and-down movement of about 1/8 inch.  In its worst state, the scores
will also move back and forth.
   Solution:  Change the 10K Ohm resistor R83 on the Vector-Generator
PCB to a 20K Ohm resistor.


STAR WARS Color X-Y Display [Amplifone ONLY; not Wells-Gardner models!]

Zero-Ohm Resistor Jumpers
   Problem:  The *brown* zero-ohm jumpers (W1 or W2) on the Deflection
PCB open up on the High-Voltage PCB.  Zero-ohm resistors look like
regular resistors, but are marked on the PCB assembly and the schematic
with a W followed by a number.
   Solution:  Replace the jumpers with pieces of wire.  Note that the
/white/ and /tan/ jumpers are good and don't have to be replaced.

Capacitor Failure
   Problem:  Capacitors C3 and C4 on the High-Voltage PCB may be
defective.  These are rated at 100uF, 35V.
   Solution:  Change C3 and C4 to 220uF, 35V with a low E.S.R.
(Effective Series Resistance) rating.  The Atari part no. is
123009-227.  The following manufacturers' capacitors will also work:

Illinois Capacitor, part no. 227 RMR 050M (50V)

Nichicon, part no. UPA1V221M (35V)

[NOTE:  Digi-Key also sells "HFS SERIES Low Impedance" capacitors which
will work.  Dial 800.DIGIKEY and order part number P1339; my last
catalog (April 1994) lists them for $1.68 each.  The Nichicon capacitors
should be obtainable from TTI.  TTI is the nations largest distributor
of passive components such as resistors and capacitors.  Dial
800.CALL.TTI to place an order.]

* (c) 1983 Lucasfilm, Ltd. and Atari, Inc. All rights reserved.
Trademark of Lucasfilm, Ltd. used by Atari, Inc. under license.

\\\ A Warner Communications Company
FOR FURTHER INFORMATION CALL: (800) 538-1611
                              (800) 943-1120

================================================================================

The following information is excerpted from a photocopy of a photocopy
(of a...)  which has no visible attribution or copyright.  It appears to
be from the Star*Tech Journal but I don't know for sure and the guy who
sent it to me doesn't know where it came from.

================================================================================

STAR WARS DISPLAY
PROBLEMS

Problem:  No filament voltage from the high voltage (HV) PCB.
Solution:  Check for a loose connection on the lugs that hold the HV
transformer to the PCB.

Problem:  Can any other power transistors be used on the Deflection
board?
Solution:  Yes, MJ 15003 NPN replaces 2N3716, and MJ15004 PNP replaces
2N3792 [NOTE:  these substitutions are valid for the Wells-Gardner
model, too].

Problem:  What should the output of the 555 IC on the HV PCB be?
Solution:  The output at pin 3 of the IC should be a 20-kHz square wave.
This is adjusted with potentiometer R7.

Problem:  There is no high voltage.  The positive and negative 24 volts
are present.
Solution:  Check transistor Q3.  The problem may be that the transistor
tab (collector) may not be making good contact with the heat sink.

Problem:  The schematics for the HV cutoff circuit do not match the
board assembly.
Solution:  There are three board revisions.  You can tell which one you
have from the table here.  The schematics for all three boards are
shown.

   DISPLAY REVISION INDICATORS
---------------------------------------------
PCB Revision   R16        R18
---------------------------------------------
Original       470 Ohms   27K Ohms
First rev.     Zener      Missing or 27K Ohms
Second rev.    470 Ohms   33K Ohms

                     o 24V
 |                   |
 |      R15    CR2   |
 +-----/\/\-----|<---+
 |                   |
\ / Q4             c \ Q5                 HV PIN 4
--- MCR100-3          =|------+-------+--------+----->
 |                 e / 2N3904 |       |        |
 +                   |        \       |  C10   \
 |\                  |        / R18  === 0.1uF / R19
 | \        R16      \        \ 27K   |  50V   \ 68K
 |  +-------/\/\---->/ R17    /       |        /
 |  |       470      \ 1K     |       |        |
 |  |                /       ===     ===      ===
 | ===  C9           |        =       =        =
 |  | .01uF          |
 +--+                |
    |                |              DAG GROUND
   ===               +------------------------------->
    =
                   ORIGINAL

                     o 24V
 |                   |
 |      R15    CR2   |
 +-----/\/\-----|<---+
 |                   |
\ / Q4             c \ Q5                 HV PIN 4
--- MCR100-3          =|------+-------+--------+----->
 |                 e / 2N3904 |       |        |
 +                   |        o       |  C10   \
 |\                  |               === 0.1uF / R19
 | \     1N754 /     \       R18      |  50V   \ 68K
 |  +-------+->|---->/ R17            |        /
 |  |       |  /     \ 1K     o       |        |
 |  |       \        /        |      ===      ===
 | ===  C9  /        |        |       =        =
 |  | .01uF \ 1K     |        |
 +--+       /        |        |
    |       |        |        |     DAG GROUND
   ===     ===       +--------+---------------------->
    =       =
                FIRST REVISION

                     o 24V
 |                   |
 |      R15    CR2   |
 +-----/\/\-----|<---+
 |                   |
\ / Q4             c \ Q5                 HV PIN 4
--- MCR100-3          =|------+-------+-------------->
 |                 e / 2N3904 |       |
 +                   |        \       |  C10
 |\                  |        / R18  === 0.1uF
 | \     R16       \---\      \ 33K   |  50V
 |  +----/\/\---+   / \       /       |
 |  |    470    |    | 1N754  |       |
 |  |           |    |        \      ===
 | ===  C9      |    |        / R17   =
 |  | .01uF     +----+     +->\ 20K
 +--+                |     |  /
    |                \     |  |      DAG GROUND
   ===               / R19 +--+---------------------->
    =                \ 1K
                     /
                     |
                    ===
                     =
               SECOND REVISION

Problem:  The schematic for the deflection board shows CR5 as a 1N714
diode.
Solution:  The schematic number is wrong.  It should be labeled a 1N751A
zener diode.  The rating of 5.1 volts is correct, however.

Problem:  On the HV PCB, the output voltage of the regulator is good
when the pin is lifted, but there is no voltage when the pin is
connected back to the board.
Solution:  Check for bad 0.1uF glass capacitor across the voltage
regulator.  The decoupling capacitor may be shorted.

Problem:  The 24-volt regulator has failed.
Solution:  Check for cracking around the regulator leads on the PCB.
Also check for cracking around the leads of C3 and C4.

Problem:  The voltage is low on the supply lines on either the
Deflection PCB or the HV PCB.
Solution:  There are jumpers on the supply lines of both boards.  The
jumpers are marked with a "W" on the schematic.  They look like
resistors on the board and have a single black band on them.  The
jumpers should have no resistance.  However, the brown jumpers may have
created some resistance to them.  They should be replaced with a piece
of wire.  The white and tan jumper should have no problems.

Problem:  The picture shrinks in from the negative X and Y sides of the
screen.
Solution:  On some deflection boards, R35 and R12 may have a 15 Ohm
resistor and a 30 Ohm resistor in parallel to get 10 Ohms.  If these
come loose, then some picture shrinkage may occur.

================================================================================

Unfortunately that's all I have for the Amplifone.  It is worth noting
that I recently acquired a copy of the Empire Strikes Back manual which
includes the previous tech tip (2 sections above) in a condensed form
that is mostly the same (it advocates replacing C3 and C4 as a matter of
course, rather than waiting for them to cause a problem).  Now I'll talk
about specifics and what devices I often find bad in the Wells-Gardner
color vector monitor.  If you don't have a manual for this monitor, get
a copy, as it does a good job of explaining how each section works and
also how to adjust it.

For you people who don't like reading manuals, or who don't feel like
locating local sources for specific parts or who don't want to hunt
through a huge catalog to put together part numbers for an order, you
can order everything you (probably) need (except for the upgrade parts
and the extra capacitor for P329 versions of the HV unit) bundled
together in one package from ZANEN ELECTRONICS.  I suggest you order a
couple of these to keep as spares since you never know when you might
need to do a rush repair job and the price simply cannot be beat.

Call them at 806.793.6337 and ask for "get well kit #206" which at last
count had 30 pieces including all the capacitors that go bad, 6
replacement chassis transistors, several of the smaller transistors (and
their corresponding resistors), several diodes (including ZD902), and
also (rather sparse) documentation on how to replace the parts.  Please
be careful if you decide to replace R918 (25K potentiometer) in the HV
unit; it needs to start out adjusted to an in-circuit resistance of 5.5K
when testing the upper 2 contacts of the 3.  (this is the average of
what I find to be the normal adjustment range which is always between 5K
and 6K.  If you have it maxed out you will probably damage your unit
when you turn it on.  I'm not sure why the kit includes this part as
I've never come across a bad one yet.

Ordering a kit from them also entitles you to FREE technical assistance
and they seem to be very experienced and knowledgeable.  They take
credit cards and do not charge anything for UPS shipping (< 7 days).
You can tell them Gregg sent you if you want.  As of December 1994, the
price for this kit was $14.95 which is probably cheaper than any deal
you could put together yourself, anyway.  I should also mention that
they sell a kit for the black and white vector monitors, too,
specifically for the Electrohome G802/805 series which is "get well kit
#104".  They sell kits for most of the monitors that are/were commonly
used in the industry; I cannot recommend Zanen and their kits highly
enough.

This is a good way to go if you don't feel like doing any testing to
find out what exactly is bad.  If you replace all the parts included in
this kit, you may be throwing out a lot of parts that still work OK (but
which may be on their last legs, anyway), but you will be virtually
assured of having a working monitor when you are done.  If you get them
all in and it still doesn't work, then go through the flowchart shown
later in this document.  It is quite likely that you have a bad HV
transformer and you will have a heck of a time locating a replacement (I
have a few but they won't last long) :<

Be aware that some of the parts that Zanen will send you are from the
original spec and should not be used as this spec is known to be
deficient.  Consult the section below about how to upgrade the
deflection boards and switch out the indicated parts for the upgraded
replacements.

Here are some good parts places to get the big transistors (and other
things) that I've used before:

Allied Electronics; 800.433.5700
Digi-Key; 800.344.4539
Mouser Electronics; 800.346.6873
Newark Electronics Chicago; 708.495.7740

Mouser also has the coin door "type 47" bulbs.  Here are a few surplus
type places that I've ordered from that have great prices on things like
electrolytic capacitors that will be happy to send you a catalog:

All Electronics; 818.904.0524
Marlin P. Jones; 407.848.8236

Before we get started let me clear up something that causes a LOT of
confusion when working on monitors of all types.  All the documentation
and boards for these monitors refer to "X" as the longer axis and "Y" as
the shorter axis, independent of how the monitor is oriented in your
game.  Confusion arises because the game PCB will refer to "X" as the
axis parallel to the floor and "Y" as the axis perpendicular to the
floor and this is dependent on how your monitor is oriented.  Why is
this important to distinguish?  Well if you notice that there is a
horizontal line on your Tempest screen and you go to figure out why you
aren't getting any "Y" deflection, you must check the "Y" portions of
the vector generator circuitry on your game PCB but you need to check
the "X" portions of your monitor (deflection board)!

Some words of caution about the manuals.  I've got 3 versions of TM-183
(originals of the 1st and 2nd printings both from 1981 and a photocopy
of the 3rd printing from 1982; let me know if you have an original of
the 3rd printing that you'd be willing to sell).  Also, if you are lucky
enough to have a copy of the Wells-Gardner service manual for this
monitor, the parts list on page 31 has an error; it lists C916 as .35uF
when it is really .035uF.  It is labeled properly in the schematic on
page 28.  None of the manuals show all the different versions of this
monitor.

Since the 3rd printing is uncommon, I will describe the significant
differences from the 2nd printing (not noting the layout changes such as
replacing the crummy photographs with clear, sketched, exploded-view
diagrams and minor rephrasings that are sprinkled throughout).  All
figures show later versions of all boards with the exception of Figure
13 which still shows the old deflection board (even though the parts
list and everything else refer to the newer versions; obviously a
mistake).  Section 3 (Adjustable Controls) describes a later version of
the neck board (P328).  Section 5 (Purity, Convergence, and Tracking
Adjustments) is completely rewritten and is MUCH less vague and more
complete (2 pages longer).  Section 6 (Details of Operation) has a
section which discusses the Input Protection Circuit and has a schematic
(Figure 8), too.  There is also a new section G (Over-Voltage
Protection) which describes the new circuit in the later version of the
HV unit (P324).

The 3rd printing fixes some typos in the deflection PCB parts list:
"(R606, 706)" split off to "4.7K Ohms, +/-5%, 1/4 W Resistor (R606)". (*)
"(R612, 613)" changed to "(R612, 613, 712, 713)".
"(C604, 704)" changed to "(C104, 105, 604, 704)".
"(C800, 801)" changed to "(C800[-]803)".
"7-Circuit Header Connector (P100, 600, 700)" added.
"(Q600-602)" changed to "(Q600-602, 700-702, 801, 802)".
"(C600, 601)" changed to "(C600, 601, 605, 700, 701)".
"4.7K Ohm, +/-5%, 1/4 W Resistor (R813)" added.
"(R602, 603)" changed to "(R602, 603, 607, 702, 703, 707)".
"Ferrite Bead (FB600)" removed.

Unfortunately, it also introduces one!
"D104, 105" changed from "Type-1N914B" to "Type-1N4001".
DO NOT MAKE THE ABOVE SUBSTITUTION AS IT WILL NOT WORK!!!!!

(*) R606 is incorrectly listed in all manual versions as being 1/4W when
in reality it is always 1/2W.

Some changes were also due to parts upgrades and/or additional circuitry:
"(Q800)" changed to "(Q800, Q805)".
"Type MPSA56 PNP Transistor (Q101)" changed to "PNP Transistor (Q101)".
"Type-1N914B Diode (D104, 105, 600, 601, 700, 701, 801[-]804)" changed to
"Type-1N914B Diode (D600, 601, 700, 701, 801-806, 809-812)".
"Type-1N4001 Diode (D106, 107, 602, 702)" changed to
"Type-1N4001 Diode (D104-107, 602, 702)".
"Type-2N3904 NPN Transistor (Q804)" added.
"10K Ohm, +/-5%, 1/4 W Resistor (R812, 813)" added.
"...2W Resistor (R106)" changed to "...3W Resistor (R106)".
"5-Amp ... (F100, F101)" changed to "6.25 Amp ... (F100, F101)".
"18K Ohm, +/-5%, 1/4 W Resistor (R811)" added.
"30K Ohm, +/-5%, 1/4 W Resistor (R810)" added.
"Germanium-Special Diode (D807, 808)" added.

There are several manufactured variations (and many more upgrade
variations) of each of the 3 boards (at least 3 for the deflection board
and 2 for the other 2) The original designs are labeled P31X and the
newer, more fault tolerant designs are labeled P32X.  I also recently
discovered a small cache of replacement deflection boards labeled P339
so there may be a whole 33X series, too!  To add to the confusion, the
Wells-Gardner service manual for "19K6400 series color vector monitors"
shows a P341 version of the neck board, a P324 version of the HV unit,
and a P322 version of the deflection board; I have never seen any of
these versions.

Here is how to identify the versions of the boards that I have seen.
The deflection boards are P314, P327 and P339.  Some P314s were upgraded
most of the way to P327s with a small piggy-back PCB on wire "stilts" at
the top of the PCB (see "Input Protection Circuit", described later in
this document).  The neck boards are P315 and P328 (P328 has a
brightness adjustment in one corner) and the HV power supply boards are
P316 and P329 (P329 has an LED, HV limit pot, and an extra electrolytic
capacitor, C22, which is supposed to be 10uF at 63V).  After much very
disturbing feedback about the performance of the monitors, Atari had all
the boards redesigned to be more robust.  The P32X (and P339) versions
are the newer versions of the boards.

A close inspection of the P339 deflection boards reveals that they are,
in reality, P327s with a P339 sticker covering the part number!  I have
verified that the PCBs are identical but have noticed several (possibly
not all) differences between components on the 2 versions.  Make the
following changes on your P327, put a new label on it and you will have
a virtual P339!  All other components except for the diodes (didn't
check them because they are too hard to read but it is extremely
unlikely that any are different) are the same.

Differences between P327 and P339 deflection boards:
C800-803 changed from .47uF @ 35V to 1uF @ 50V. (*)
R701 (1.3K) changed from +/-2%, 1/4W to +/-1%, 5W. (*)
R812-813 (1/4W) changed from 10K +/-5% to 5.6K +/-10%. (*)
Q604/Q704 (NPN) packages are upgraded from TO-92 to TO-202 (NTE49). (*)

If you have a P314 board, in addition to the changes listed above, you
should upgrade the following parts.

Differences between P314 and P327 (P339) deflection boards:
"Input Protection Circuit" added (see additional text later on).
R106 (22 +/-10%) changed from 2W to 3W.
Q101 (PNP) changed from Type MPSA56 (TO-92) to NTE50 (TO-202). (*)
F100, 101 (Slow-Blow) changed from 5A to 6.25A.

(*) The Zanen "Get Well Kit" uses the original specs and does not
include these upgrades.

Since the circuits are essentially the same and since I have used 5 Amp
fuses in P339/327 boards without any problems, it is safe to say that
you can (and more importantly, probably should) put 6.25 amp fuses in
your P314 boards at those 2 locations.

The very first run of P314 deflection boards had design defects in them
which were evidently identified after the PCBs were produced but before
they were populated (I make this assumption because I have never seen a
board which did not have the corrections/substitutions on it).  Anyways
if your board says "85X0147" at the top then it is from the very first
batch.  Later batches say "85X0147C" (I have never seen an "A" or "B"
flavor).  The "C" flavor has C605 (.001uF +/-20%, Type-Z5F capacitor) in
the upper right corner but since the plain flavor doesn't have a spot
for it, it was soldered piggy-back onto R602.  Some boards use a .005uF
capacitor instead but you should change this to a .001uF if you have the
soldering iron out anyway.  The plain flavor has ZD100 labeled as R104
and ZD101 as R105, respectively, even though there are always Zener
diodes in those spots regardless.

A comparison of the P315 and P329 versions of the HV PCBs and their
documentation yields several conflicting differences which are
summarized below.  The values marked with an asterisk (*) are the ones I
suggest you use regardless of which PCB you are working on (with the
caveat that the resistors should be "matched"; don't just change the
value of one without changing the values of all the others.  The
capacitor changes can be made individually).  If you use all the
asterisk marked values, you will upgrade your P315 to a P329 except that
you, obviously, won't have the over-voltage protection portion of P329.

+-------+--------------------------------+--------------------------+
|Part # | Value in document or on PCB    | Document/PCB referenced  |
+-------+--------------------------------+--------------------------+
|*C901  | 100uF @  50V Alum Electrolytic | P329 HV unit PCB         |
| C901  | 100uF @  35V Alum Electrolytic | P315 HV unit PCB         |
| C901  | 100uF @  50V                   | TM-183 3rd printing Sch. |
| C901  | 100uF @  35V                   | TM-183 2nd printing Sch. |
| C901  | 100uF @ 100V                   | 19K6400 service man Sch. |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 3rd printing Fig. |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing Fig. |
| C901  | 100uF @  50V Alum Electrolytic | TM-183 3rd printing list |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing list |
| C901  | 100uF @ 100V Alum Electrolytic | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C902  | 100uF @  50V Alum Electrolytic | P329 HV unit PCB         |
| C902  | 100uF @  35V Alum Electrolytic | P315 HV unit PCB         |
| C902  | 100uF @  50V                   | TM-183 3rd printing Sch. |
| C902  | 100uF @  35V                   | TM-183 2nd printing Sch. |
| C902  | < part is not referenced >     | 19K6400 service man Sch. |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 3rd printing Fig. |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing Fig. |
| C902  | 100uF @  50V Alum Electrolytic | TM-183 3rd printing list |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing list |
| C902  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C905  | 33uF  @ 160V Alum Electrolytic | P329 HV unit PCB         |
| C905  | 33uF  @ 160V Alum Electrolytic | P315 HV unit PCB         |
| C905  | 33uF  @ 150V                   | TM-183 3rd printing Sch. |
| C905  | 33uF  @ 150V                   | TM-183 2nd printing Sch. |
| C905  | 33uF  @  63V                   | 19K6400 service man Sch. |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 3rd printing Fig. |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 2nd printing Fig. |
| C905  | 33uF  @  63V Alum Electrolytic | TM-183 3rd printing list |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 2nd printing list |
| C905  | 33uF  @  63V Alum Electrolytic | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C915  | .001uF +/- 20% Type Z5F        | P329 HV unit PCB         |
| C915  | .001uF +/- 10% Ceramic         | P315 HV unit PCB         |
| C915  | .001uF                         | TM-183 3rd printing Sch. |
| C915  | .001uF                         | TM-183 2nd printing Sch. |
| C915  | .001uF                         | 19K6400 service man Sch. |
| C915  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| C915  | .001uF                         | TM-183 2nd printing Fig. |
| C915  | .001uF +/- 20% Type Z5F        | TM-183 3rd printing list |
| C915  | .001uF +/- 10% @ 500V Ceramic  | TM-183 2nd printing list |
| C915  | .001uF +/- 20% Type Z5F        | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
| C919  | < part is not referenced >     | P329 HV unit PCB         |
| C919  | < part is not referenced >     | P315 HV unit PCB         |
| C919  | < part is not referenced >     | TM-183 3rd printing Sch. |
| C919  | < part is not referenced >     | TM-183 2nd printing Sch. |
| C919  | < part is not referenced >     | 19K6400 service man Sch. |
| C919  | < part is not referenced >     | TM-183 3rd printing Fig. |
| C919  | < part is not referenced >     | TM-183 2nd printing Fig. |
| C919  | < part is not referenced >     | TM-183 3rd printing list |
| C919  | 10uF @ 300V Alum Electrolytic  | TM-183 2nd printing list |
| C919  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R901  | 3.9  +/- 5%,   3 W             | P329 HV unit PCB         |
| R901  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R901  | 3.9,           3 W             | TM-183 3rd printing Sch. |
| R901  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R901  | 3.9,                           | 19K6400 service man Sch. |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing Fig. |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing Fig. |
| R901  | 3.9  +/- 5%,   3 W             | TM-183 3rd printing list |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R901  | 3.9  +/-10%,   3 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R907  | 3.9  +/- 5%,   3 W             | P329 HV unit PCB         |
| R907  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R907  | 3.9,           3 W             | TM-183 3rd printing Sch. |
| R907  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R907  | < part is not referenced >     | 19K6400 service man Sch. |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing Fig. |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing Fig. |
| R907  | 3.9  +/- 5%,   3 W             | TM-183 3rd printing list |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R907  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R910  | 6.8K +/- 5%, 1/4 W             | P329 HV unit PCB         |
| R910  | 12K  +/- 5%, 1/4 W             | P315 HV unit PCB         |
| R910  | 6.8K                           | TM-183 3rd printing Sch. |
| R910  | 12K                            | TM-183 2nd printing Sch. |
| R910  | 12K                            | 19K6400 service man Sch. |
| R910  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R910  | 12K  +/- 5%, 1/4 W             | TM-183 2nd printing Fig. |
| R910  | 6.8K +/- 5%, 1/4 W             | TM-183 3rd printing list |
| R910  | 12K  +/- 5%, 1/4 W             | TM-183 2nd printing list |
| R910  | 12K  +/- 5%, 1/4 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R911  | 4.7K +/- 5%, 1/4 W             | P329 HV unit PCB         |
| R911  | 6.8K +/- 5%, 1/4 W             | P315 HV unit PCB         |
| R911  | 4.7K                           | TM-183 3rd printing Sch. |
| R911  | 6.8K                           | TM-183 2nd printing Sch. |
| R911  | 6.8K                           | 19K6400 service man Sch. |
| R911  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R911  | 6.8K                           | TM-183 2nd printing Fig. |
| R911  | 4.7K +/- 5%, 1/4 W             | TM-183 3rd printing list |
| R911  | 6.8K +/- 5%, 1/4 W             | TM-183 2nd printing list |
| R911  | 6.8K +/- 5%, 1/4 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R926  | 2.2  +/- 5%,   3 W             | P329 HV unit PCB         |
| R926  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R926  | 2.2,           2 W             | TM-183 3rd printing Sch. |
| R926  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R926  | 2.2,           2 W             | 19K6400 service man Sch. |
| R926  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R926  | 2.2,           2 W             | TM-183 2nd printing Fig. |
| R926  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing list |
| R926  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R926  | 2.2  +/- 5%,   2 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+

The good part of all this is that the 3 basic units, deflection board,
neck board, and HV board are all interchangeable as units and they are
all connectorized.  In other words if you have one working monitor you
can try the boards from your bad monitor (one at a time) even if the
boards are not exactly the same.  Also, the most often failing
components are common to the different versions of the boards.  If you
have a vector monitor based game, it is really worth the effort and
money to have a spare monitor handy (even if it is being used in another
vector game) so that you can isolate exactly which board is bad when
(not if) you have a failure.

Obviously, the neck board must be physically switched to be tested but
you you don't have to unscrew the ground wires of the current PCB, or
screw in the ground wires of the replacement PCB; you can just let the
current PCB dangle and use alligator clips to connect the replacement
neck board's ground wires to the chassis.  With careful placement you
can test a deflection board or HV unit without having to remove the one
already in there.  For the replacement HV unit simply connect the 3
connections and then use an alligator clip to ground the case to the
chassis.  Since you have grounded it, there is no need to attach it to
the chassis; simply let it dangle by the secondary anode wire (the one
with the suction cup) or the alligator clip but make sure it doesn't
touch anything it shouldn't (keep the exposed underside of the PCB from
touching anything).  The replacement deflection board can sit on top of
the current one separated by a piece of cardboard or other
non-conductive material but getting it in there is more hassle than
swapping so I usually pull the one that is in there and do a swap.

NOTE:  There is 1 small exception to this universal compatibility rule
for the neck board PCB.  The P328 version uses a third (purple) wire
running from the innermost (normally unused) pin of connector J501 to
pin 8 of J900 on the HV unit.  Without this wire, the new brightness
control on P328 is disabled.  Also, and this is *VERY* important, if you
are using a P328 PCB on a P315 wiring harness (or vice-versa), you have
to turn the J501 connector upside down.  Don't worry too much about
remembering the orientation because the connector's pins are gapped
differently so it will only fit onto each PCB one way (the right way)
without severely bending the pins on the neck board PCB (i.e. it is
idiot-proof).  This means that for testing purposes, you can swap boards
and everything will be fine but if you want the functionality that the
P328 potentiometer provides, you must remove the associated wiring
harness that connects to J501 along with the board (or else add a new
wire to the existing harness on the destination monitor).  Without this
wire, a P328 will behave exactly like a P315 and the pot will do
nothing.

The very first thing you should do is check all the fuses in the machine
with a meter.  There are 4 on the deflection board and most Atari
machines have 7 more in the power supply at the bottom of the machine (6
in a bay on the left and one under a black cap on the right).  Remember
to check resistance on the fuse *holder* NOT ON THE FUSE.  Many times a
fuse will meter out OK but it isn't making good contact with the fuse
holder so it is not conducting.  If you always put your probes on the
fuse holder, you will never get tricked by a bad contact.  Many times
fuses not conducting can be made to do so merely by reseating them after
pinching the fuse holder clips tighter.  Sometimes the clips are
corroded and need to be cleaned first.  The wire contacts connecting to
the fuse holders may also not be conducting properly so you may want to
move your leads and test there to cover all your bases.  This rule
applies to fuses in general anywhere you find them.

The only other components (besides the tube itself) are the six large
TO-3 package transistors mounted to the chassis ("package" refers to the
physical description of the transistor, *NOT* the electrical
characteristics).  The 3 NPNs are 2N3716s and the 3 PNPs are 2N3792s
which are all in the final stages of the deflection amps or the power
supplies.  The deflection amps are like an audio push-pull amplifier and
to power these amps the monitor takes AC in and produces plus and minus
DC voltages.

Most of the failures in this monitor (as is the case with most
electronic devices) are semiconductor failures, specifically, the
transistors.  All transistors discussed in this document can be tested
in the same way; it doesn't matter if they are the large chassis-mounted
transistors or the tiny PCB-mounted transistors.  With the transistors
out of circuit, set your multi-meter on Rx1K scale and use the following
procedures.

NOTE:  ANALOG AND DIGITAL MULTI-METERS REQUIRE DIFFERENT TESTING
PROCEDURES FOR TRANSISTORS!  For some reason, digital meters always show
infinite resistance for all 6 combinations (if you accidentally get your
skin involved it will show something around 2M Ohms).  The best way to
test transistors with a DMM is to make use of the "diode test" function
which will be described after the analog test.  For both methods, if you
read a short circuit (0 Ohms or voltage drop of 0) or the transistor
fails any of the readings, it is bad and must be replaced.

TESTING TRANSISTORS WITH AN ANALOG OHMMETER:
For type NPN transistors, lead "A" is black and lead "B" is red; for
type PNP transistors, lead "A" is red and lead "B" is black (NOTE:  this
is the standard polarity for resistance but many multi-meters have the
colors reversed; if the readings don't jive this way, switch the leads
and try it again).  Start with lead "A" of your multi-meter on the base
and lead "B" on the emitter.  You should get a reading of 2.5K Ohms.
Now move lead "B" to the collector.  You should get the same reading.
Now try the other 4 combinations and you should get a reading of
infinite Ohms (open circuit).  If any of these resistances is wrong,
replace the transistor.  Only 2 of the 6 possible combinations should
show a resistance and that value should be 2.5K Ohms; none of the
resistances should be 0 Ohms (shorted).

TESTING TRANSISTORS WITH AN DIGITAL MULTI-METER:
Set your meter to the diode test.  Connect the red meter lead to the
base of the transistor.  Connect the black meter lead to the emitter.  A
good NPN transistor will read a JUNCTION DROP voltage of between .45v
and .9v.  A good PNP transistor will read OPEN.  Leave the red meter
lead on the base and move the black lead to the collector.  The reading
should be the same as the previous test.  Reverse the meter leads in
your hands and repeat the test.  This time, connect the black meter lead
to the base of the transistor.  Connect the red meter lead to the
emitter.  A good PNP transistor will read a JUNCTION DROP voltage of
between .45v and .9v.  A good NPN transistor will read OPEN.  Leave the
black meter lead on the base and move the red lead to the collector.
The reading should be the same as the previous test.  Place one meter
lead on the collector, the other on the emitter.  The meter should read
OPEN.  Reverse your meter leads.  The meter should read OPEN.  This is
the same for both NPN and PNP transistors.  Thanks to Randy Fromm
<YMNP18A@prodigy.com> for this excellent summary of the diode test
method.

Anyway, there are 2 types of the large chassis transistors:

2N3716 (NPN); widely available replacement is NTE284
   Q705  +X (right)  for horizontal; +Y (top)    for vertical
   Q605  +Y (top)    for horizontal; -X (left)   for vertical
   Q102  output positive (+) power supply

2N3792 (PNP); widely available replacement is NTE285
   Q706  -X (left)   for horizontal; -Y (bottom) for vertical
   Q606  -Y (bottom) for horizontal; +X (right)  for vertical
   Q103  output negative (-) power supply

SPECIAL NOTE:  Q705 and Q102 lie in such close proximity that it is not
uncommon for their respective transistor sockets to be switched at some
point which obviously swaps the corresponding functionalities
(symptoms).

This gives reference frames for when the monitor is mounted horizontally
(for games like Space Duel and Major Havoc) and vertically (for games
like Tempest and Quantum).

For those of you without a manual, here is how to identify which one is
which.  The following descriptions are relative to the monitor oriented
horizontally on it's base (like a TV would sit and like it is inside
most games) and viewing it from the back side (so that you see the
components and not the picture).  2 of them are on the outside of the
chassis on the right side.  The one nearest the back (component) side is
Q606; the one nearest the front (viewing) side is Q605.  On the inside
of the bottom of the chassis are the other 4.  The one on the far left
nearest the HV unit is Q706.  The one on the far right nearest the first
2 is Q103.  The other of the 2 remaining middle ones which is closest to
the back is Q102 and the last one which is in the same area but is
closer to the front of the monitor is Q705.

An easy way to remember which kind of transistor goes where is to know
that each connector has one of each kind; the 2N3716s are on pins 1, 3,
and 4 (key at pin 2) and the 2N3792s are on pins 5, 6, and 7.  If the
wiring has not been altered, all 2N3716s are connected to the yellow,
green, and red wires and all 2N3792s are connected to the purple, blue,
and white wires.  Here are 2 diagrams of the layout as viewed from the
top:

+--------------------------------------------------+---------------------+
|             (front; Picture Tube)                |                    /
|                  2   _                           |  2   _            /
|                  N  / \                          9  N  / \          /
|                  3 / Q \                         0  3 / Q \        /
|                  7| 705 |                        |  7| 605 |      /
|                  1 \   /                         d  1 \   /      /
|                  6  \_/                          e  6  \_/      /
|      2   _                            2   _      g 2   _       /
|      N  / \                           N  / \     r N  / \     /
|      3 / Q \                          3 / Q \    e 3 / Q \   /
|      7| 706 |                         7| 103 |   e 7| 606 | /
|      9 \   /                          9 \   /    | 9 \   / /
|      2  \_/                           2  \_/     b 2  \_/ /
|                  2   _                           e       /
|                  N  / \                          n      /
|                  3 / Q \                         d     /
|                  7| 102 |                        |    /
|                  1 \   /                         u   /
|                  6  \_/                          p  /
|                                                  | /
|                   (back)                         |/
+--------------------------------------------------+

or, more simply (where 2=2N3792 and 6=2N3716):
            _________________
           /      FRONT      \
          |   Picture Tube    |
          |-------------------|
          +-----+   6  +-----+6
          |HV   | 2    |Def.2||
          |Cage |   6  |PCB  |2
          +-----+------+-----+-

These transistors often go bad and here is a quick lesson on how to
check a transistor with a meter.  Unplug the red plugs from the
deflection board to isolate the transistor from the circuit.  From the
bottom of the transistor, the configuration is (Oh boy; time for a
picture!):
          _
         / \
base -> /o o\ <- emitter
       |     |
        \   /<- the case is the collector
         \_/

Pretty crude but you get the idea I hope.  Test the transistors as
described earlier, one by one, by placing the multi-meter leads on the
tops of the pins of the red connectors or on the transistors themselves.
Neither method requires the removal of the transistor from its socket so
don't bother.  You do, however, need to disconnect the associated
connector from the deflection board prior to testing.

So what symptoms go with what?  Well if only one of the deflection
amplifying transistors goes then you will lose the corresponding half of
the screen (for example if Q705 went bad in a Tempest game, you would be
missing the top half of your screen).  It won't actually be gone; it
will be collapsed into a line across a 0 axis of the screen.  If more
than one goes or either of the power transistors (Q103 or Q102) goes you
will get no picture because the spot killer turns on (and the LED on the
deflection board lights) and shuts down the electron beam.

Checking these transistors is one of the first things you should do if
parts of your screen are missing or your spot killer is on.  Exact
replacements are nice but I've successfully substituted others
especially if you put the nonstandard transistors in the place of Q102 &
Q103 as those two are for the + & - power supplies and not as critical
(image-wise) as the ones that drive the deflection coils.

When replacing these transistors, make sure the socket is centered.
Don't forget the little rubber or clear mica (plastic) insulator that
was stuck to the chassis or to the bad transistor you just removed.  You
need to grease this insulator on both sides with a special grease called
Silicone Heat Sink Compound.  It is not strictly necessary but helps
transfer the heat from the transistor to the chassis so the transistors
last longer.  The grease is pretty expensive so you may want to just buy
new insulators (they should be about 10 cents each) because most come
"pre-greased".

Don't be nervous about remembering the orientation; the pins are off
centered in order to make the connection somewhat idiot-proof (see
earlier ASCII picture.  They are obviously "handed" but can be put in
upside-down; it is a tight fit and hard to do but possible).  Also,
after you replace these and before you power the game up, use your meter
to make sure none of the cases of the transistors are shorted to the
chassis.  This is very common and will cause fuses to blow and will
probably destroy the transistor.  If any part of the transistor is
touching the chassis you are asking for trouble.

On the deflection board, the most common failures are Q100 and Q101 and
when these go they take R100 and R101 (respectively) with them.  These
transistors are part of the + & - power supply circuit and are often bad
with the resistors really burnt.  To properly test these, they should be
desoldered and removed from the PCB.  Even in-circuit and not isolated
from other components you can still get a pretty good idea with a
multi-meter (analog meters work best since digital meters show infinite
resistance most of the time) if the transistors are bad as transistors
tend to fail catastrophically.  In other words, they usually completely
short (0 Ohms) or open.  If you see 0 Ohms where there should be an open
circuit or 2.5K Ohms, then the transistor is probably shorted.  If you
see greater than 2.5K Ohms when the reading should be in that range the
transistor is probably open.  When these transistors are bad, they
usually show a large crack in the case if you look closely at them.

Replace Q100 with the same type transistor but if Q101 is bad (and even
if it is not), I *strongly* suggest you upgrade it to a larger
transistors that will handle more current.  I *ALWAYS* replace Q101 with
a TO-202 package instead of the much smaller TO-92 package that the
board comes with.  In fact, the P327, and P339 versions were
manufactured with this upgrade.  The 3 labels I have seen are 119;NSDU57
(National Semiconductor) and M152;126-1A ("brandless"?), and NTE50 (NTE)
[semi-colons denote a new line of text found underneath the previous
line].  I always use NTE50s as they are relatively cheap and very easy
to find.

Even though these transistors (and resistors) are the most common
failures on the deflection board, I have *never* seen them go bad after
Q101 was upgraded to a NTE50.  If you can't find the generic parts, a
common modern day replacement for MPSA06 (Q100) is NTE287 and a common
modern day replacement for MPSA56 (Q101) is NTE159 (but I cannot stress
enough the utility of going with the larger replacement for Q101).
Upgrading Q101 is always the first thing I do to any deflection board I
get; replacing it before it fails saves me from having to replace the
other parts that go bad when it does fail.

Once in a while you will see D105 or D104 open or shorted, too.  Also
watch for broken solder joints at the base of the connector pins for all
the major connectors (especially on the deflection boards of black and
white Wells-Gardner units which almost always are bad).  You tend to
rock the plugs back and forth when you pull the connectors and this
often cracks the solder joints to the circuit boards which were poorly
soldered to begin with.  You may also want to check each pin for
continuity with the next component on its trace line (and also with
adjacent pins), and remove and resolder any dubious connections.  While
you are at it, resolder the 3 pins of the PTC thermistor (in the middle
along the left edge of the deflection board) as they are almost always
loose for some reason.

It is unusual but sometimes some of the 4 heat sinked (or is that "heat
sunk"?) transistors on the deflection board will die.  If any of these
is bad, you will usually get no picture at all but you will see
"background brightness" that lets you know some electrons are being
thrown at the tube.  Be sure to check the resistors and diodes around
any bad transistors you find.

Usually, the electrolytic capacitors are still OK (though always be
suspicious of electrolytics drying up and loosing micro-Farads).  If the
transistors in the chassis are OK, most missing pictures are due to
problems with this board (whereas most distorted pictures are due to bad
capacitors in the HV unit).  I frequently see HV units with the
protective shield removed from the case and discarded in attempt to keep
it cooler.  I like to keep mine on because I rate dust and foreign
object attraction as a more severe problem than heat for this board but
like I have said, I don't let my stuff run hot.

Very infrequently, you may have problems with some other transistors in
the X/Y amp section of the board.  Most of the rest of the transistors
that populate the deflection board (Q600-602,700-702) are type TPS98 and
are not easily found anymore.  The good news is that TPS98 is equivalent
to the PN3569 and the ECG or NTE 194.  All Electronics (800-826-5432)
has PN3569 transistors at 5 for $0.50.  Note also that All has just
dropped their minimum order requirement (still $5 S&H on most orders,
though).

The neck board very seldom has problems.  The few I've seen are from
mishandling where someone has broken some of the pots that control the
RGB drives.  Check the pots if you are missing a color.  If you are
blowing your 5A fuses and your other boards are OK, check C503 (33 uF
@ 250V).  If this is open, shorted or cold soldered, it will cause the
5 (or 6.25 depending on your board) fuses to blow.

Last is the HV supply.  I've worked on lots of these and have only seen
one of the infamous bad HV transformers.  Normally HV failures are due
to a semiconductor or capacitor failure.  I must mention that the HV
unit can put out very weak X-ray radiation and and creates lots of ions
in the air but both are in sufficiently small quantities that there is
little risk of injury.  Nonetheless, many people feel a tad queasy
during or after working near high voltage.  Like anything else, it gets
less noticeable with successive exposures.  Many people are quite
worried the first time they experience the sensation but it is harmless.
Please note that I am not a doctor nor a radiation specialist so refer
back to the CYA clause at the beginning of this document.  Certain
unlikely faults that I have never run across could cause large amounts
of X-rays to be produced which would definitely be harmful.

Before you work on this beast, discharge the tube as it can really zap
you even when turned off (it is extremely inadvisable to work on the HV
section while the machine is on or even plugged in; always unplug the
game before you go in here).  Connect a clip lead between the chassis
and the shaft of a long narrow plastic-handled screwdriver.  Work the
end of the screwdriver under the big suction cup on the top of the tube
until you hit metal.  There will often be a snap (from the spark) as the
HV runs at around 20 thousand volts.  Just go slowly and use only one
hand.  It won't bite as long as you are careful.  You may want to leave
the game plugged in BUT TURNED OFF for this step so that you can ground
to the earth instead of just the chassis.  If you plan to remove the HV
unit, you must disconnect the secondary anode from the tube which is a
little tricky.  Under that suction cup is a double-barb.  The barbs
extend perpendicular to the wire as it enters the suction cup.  Simply
pinch the suction cup as best as you can and wiggle it back and forth
while pushing in at the edges and pulling out at the center.  It will
eventually come off.  Here is a cut-away depiction of the anode; the
wire will run perpendicular to this view (i.e.  towards/away from the
reader):
                         |    /\   /\    |
                          \     \ /     /
                           \____|_|____/

When I was in the habit, I discharged the tube with my HV probe so I
could watch the voltage go down as the internal resistance of the probe
bled the voltage off slowly.  If the snap bothers you, put a resistor in
series with your clip lead to drain off the voltage more slowly.  If you
don't have this equipment available, a 1 or 2 hour wait after unplugging
the game should be sufficient for most of the excess charge to bleed off
naturally.  NOTE:  The anode is designed to hold onto charge so it will
*never* discharge completely without being deliberately grounded.  In
fact, if you wait a couple of days after grounding it, it will actually
build up another (small) charge!  I suggest that if you go through the
trouble of discharging it, you should keep it grounded by using an
alligator clip on the end of your wire and leaving it connected to your
ground.  This way you have no chance of getting shocked (just be
ABSOLUTELY CERTAIN to remove this ground wire before you turn the power
back on again).

Personally, I never worry about any of this anymore since the shock
(when received properly) is harmless and mostly painless (I have gotten
zapped dozens of times).  Just make sure the game is unplugged first.
If you aren't going to wait, follow the "1 hand rule"; only use one hand
when disconnecting the cable and keep the other one in your pocket or in
the air.  The only likely way for the charge on an unplugged machine to
hurt you is for it to form a circuit between your 2 hands (one grounded
and one on the tube) sending current directly across your heart; these
levels could easily interfere with your heartbeat and even cause it to
stop!  I should also point out that black and white monitors use
significantly lower high voltage than do color monitors and raster
monitors have high voltages that are and order of magnitude higher than
vector monitors use.  I have been shocked by them all and assure you
that rasters *definitely* have a bigger sting than do vectors so beware!

The following flowchart is excerpted from a photocopy of a photocopy
(of a...)  which has no visible attribution or copyright.  It appears to
be from the Star*Tech Journal but I don't know for sure and the guy who
sent it to me doesn't know where it came from.

================================================================================

_TEMPEST_ DISPLAY

Most problems in the Tempest display can be found by following the
procedure shown in the chart below.

CAUTION:  When replacing the transistors mounted on the chassis, make
sure the pins do not short to the chassis.  If the chart procedures do
not solve your problem, call Atari Field Service [NOTE:  They will be of
little help nowadays :>].

[NOTE:  I have taken considerable liberty in restructuring the flow and
rewriting the text in order to be more clear than the original chart and
to better fit in 80 column text format.  I have added a couple of
things, too.]

                          No picture and...
         +--------YES---- 5 amp fuse (F100 or F101)----NO-------+
         |                on Deflection PCB blows?              |
        \|/                                                    \|/
Cannot get/keep +/- 28 Volts.           Turn up brightness and contrast controls
Disconnect P600, P700, and<--------+    on HV PCB.  Is there a dot in the center
P100.  Power up monitor.           |    of the screen?-----------------+
         |                         |        |        +-------+         |
        \|/                        |     NO |        |       |     YES |
Fuse still blows?-------NO-------+ |       \|/      \|/      |        \|/
         |                       | |    Is there +/- 28V on  |  Is there 180V on
     YES |                       | |    on pins 1/8 of P900? |  pin 5 of P900?
        \|/                      | |        |        |       |     |        |
Replace the following components | |     NO |    YES |       +-----+ YES    | NO
if shorted: D100, D101, D102,    | |        |        |                      |
D103, C100, and C101             | +--------+        +----------------------+
         |                       |                   |
         +-----------------------+                  \|/
        \|/                             Change or make sure C901 and C902 are
Check for Q102/3 collector short to     100uF at 50 volts.  Check for a leaky
chassis.  Replace the following compo-  C905.  If C905 is bad, also check or
nents if defective: Q100, Q101, D104,   replace Q900, Q901, Q902, Q903.  Is
D105, ZD100, ZD101, Q102, and Q103.     there 180 volts on pin 5 of P900 now?-+
         |                                                         |          |
        \|/                                                     NO |      YES |
Connect P100 and power up.  Is                                     |          |
the +/- 28V on pins 4/5 of P100         Check resistors R100,      |          |
OK now?--+--------------NO------------->R101, R102, and R103       |          |
         |                              for open circuits.         |          |
     YES |                                      |                  |          |
        \|/                        +------------+                  |          |
Replace the following components   |                              \|/         |
if defective: Q603, Q605, Q606,<---+    Double-check the above transistors.   |
Q703, Q705, Q706.                       Also look for burnt (open or shorted) |
         |                              resistors R903, R904, R905, R906, or  |
        \|/                             R907.            |                    |
Connect P600 and P700 and power                          |                    |
up.  Picture now?-------YES--------+---------------------+--------------------+
         |                         |
    NO   |                         |    Is picture "blooming" (does the image
        \|/                        +--->appear as though being viewed through
Check remaining transistors        |    a magnifying glass)?         |
in the X and Y amplifiers.         |         |                       |
Then make sure the following-------+      NO |                   YES |
resistors are not open: R702,               \|/                     \|/
R703, R711, R712, R602, R603,              >END<----Replace ZD902 on HV PCB.
R611, and R612.                             / \

================================================================================

Let's finish off with a troubleshooting guide broken down by symptoms.
Much of the rest of this section is a transcription of repair notes from
a Wells-Gardner technician.  Just because your symptom matches something
in here is no guarantee that what I/he found wrong is the same thing
that is wrong with your board, but it's a good place to start.  Most of
the problems he listed in his notes were due to manufacturing defects or
incompetent repair work.  Obviously, if your monitor was working OK and
then simply stopped, those things are not likely be your problem.  If
you have seen any problems that are not listed in this section, please
contact me and I will add them.

Display "implodes" during intermission screen between player one and
player two and sometimes on the "figure 8" levels (Tempest machines
only):  I thought I knew what was causing this but upon further
evaluation, my solution didn't make sense (although it did work for me
the only time I had this problem).  Until I get another board to fix
that has this problem, I only have general advice on how to avoid the
problem.  Adjust your game board and "shrink" the Y deflection some and
this should help.  There are 2 sets of ROMs for this game and the
"compact" ROM set (only half the ROM sockets are used) is slightly
different (the intermission screen has some other stuff such as the
copyright and credits information at the bottom of the screen which
"balances" it out) so the spot killer won't get confused and decide that
the bottom half of the screen is wiped out.  These PCBs do not normally
experience this difficulty.

The following section lists problems with the deflection board.

Fuses F100 and/or F101 are blowing as soon as game is powered up:  This
happens to a lot of people after they replace the chassis transistors.
Sometimes they forget to put the mica (plastic) insulator on the
transistor before installing them which allows the transistor's case
(collector) to short to the chassis (ground).  A short can be present
even if the insulator was installed if the conditions are just right.
Check all chassis transistors, particularly Q102, Q103, to make sure the
cases are not shorted to the chassis.

Spot Killer LED lights and you don't have any display on the screen at
all:  Check the fuses first.  If they are OK, then check the 6
transistors mounted on the chassis as described earlier.  If you find at
least 2 of the deflection ones or 1 of the power ones bad, then that is
definitely tripping the spot killer.  A good trick to figure out where
the problem exists is to turn your brightness up all the way and see
what your picture looks like.  The spot killer doesn't turn the Z signal
all the way off so if you turn the brightness all the way up, you should
be able to see a very faint picture.  Based on what the picture looks
like, you can decide which half of the circuit is causing the problem
(either the X or Y portion).  If you know it is a problem on your
deflection board (i.e. swapping another board in makes the monitor
work) then check R808 (X) and R809 (Y) to make sure they are not open.
These resistors allows current to flow to the spot killer circuitry and
if they open then the spot killer thinks something has happened to the
amplifier circuitry so it kicks on.  You can tell if this is your
problem by turning the brightness on all the way; if you see a complete
picture, then this may be your problem.  If all this is OK then you
probably have a game board problem, particularly if you are unable to
"play" the game (see the credit lights blink after you punch up credits
and hear the game sounds after you push start).

Zanen kit installed but still no picture (spot killer may or may not
light):  The problem is most likely Q603.  Occasionally you will see
Q603 (Q703), or Q604 (Q704) go bad.  If one does, be sure to check the
resistors and diodes around it, particularly R611 (R711), R612 (R712),
and D602 (D702).  A common modern day replacement for MPSU57 (Q603/Q703)
is NTE189 and the part for MPSU07 (Q604/Q704) is NTE188.  These should
be greased where they touch the heat sink (like the chassis transistors)
to improve heat dissipation.  If you are having trouble with these
failing, you might want to beef them up by using TO-202 package upgrades
to NTE50 (MPSU57) and NTE49 (MPSU07).

No X (or Y) deflection:  I have seen 1 board like this and the problem
was that R710 (R610 for Y) was open.  How you fry a 10 Watt resistor and
nothing else in the circuit is beyond me; perhaps the PCB was dropped
and it landed on R710.  Anyways, you can test it in circuit and if you
don't see a virtual short then replace it.

Jeff Young from World Wide Distributors in Grand Rapids, MI reported
some words of caution about these resistors on Page 3 of the November
1982 issue of the Star*Tech Journal:

================================================================================

After fighting a problem in the Atari "Tempest" for three days and
finding a silly mistake, I thought I should write to you.  Wells_Gardner
Monitors #19K6101 use a 1.5-ohm 10-watt resistor in location R610-R710.
If you replace these resistors with standard wire-wound units, the
monitor will exhibit the "shakes" or "jitters" referred to in S*TJ, VOl.
4, No.  7 "Service Tips", but the symptoms will be misleading in that
R601 and R701 must be *Non-Inductive*.  Please tell your readers about
this problem as Atari and Wells do not point out this requirement in the
parts listing, and only put down the initials, "N.I" on the schematic.

================================================================================

R101 glows red hot and burns up to open circuit every time the game is
powered up (known good deflection board; works in good monitor):  The
resistor is burning up because of runaway current from the HV unit.  You
can confirm this by replacing R101 and testing the deflection board in a
known good monitor (or by putting a known good HV unit in the monitor
that is acting up); if R101 doesn't burn up then you know the HV unit is
the culprit.  Whenever this has happened to me, R903 in the HV unit has
been the cause.  It will sometimes short and this causes so much current
to flow to the deflection board that the puny 15 Ohm resistor burns up.
If this goes on for too long, Q101 may fail or occasionally R901 will
burn up to an open circuit.

Accidentally shift P101 over 1 pin and power up machine:  Although most
of the connectors/connections are idiot-proof, P101 is not (due to the
poor placement of the key pin as the *last* pin).  It can be connected
shifted over 1 or more pins to the right (although it should be obvious
if you shift it more than 1 pin).  After shifting it 1 pin and frying
the PCB, when you hook it up correctly, the spot killer LED will glow at
50% brightness and you will get no video.  The following parts will need
to be replaced; Q703, R711, D702, and C703 (C703 should be OK but
replace it just in case if you can find a new one).  Some caps may have
blown on the HV board, too.

Distorted image which exists ONLY in the lower right quadrant of the
display:  I have seen this several times and the problem has always been
a bad ZD101.  Much of the time this causes R101/Q101 to fry and spot
killer comes on.

The following section lists problems with the neck board.

Color problems:
   Colors drop in and out; ZD500 (open; neck board)
   Display is too bright;
      R515 (broken wire to R531; neck board)
      C503 (reversed; may toast R527; neck board)
   No red; check:
      on neck board:
         R500 (open)
         R502 (shorted to nearby component)
         R510 (open)
         R511 (open or wrong value)
         R520 (open; red color can be seen but is very weak)
         R529 (open or wrong value)
         broken wire at R517 control
   Only red; check:
      on deflection board:
         D802 (reversed)
   Red too bright; check:
      on neck board:
         R501 (wired wrong)
         R504 (open)
         Q500 (collector shorted to base)
   Red does not turn off when dimmed all the way; check:
      on neck board:
         Q500 (reversed or broken wire)
         R513 (shorted to C500)
         R519 (open)
         R529 (open)
   No green; check:
      on deflection board:
         neck board connector wrong type
         broken green wire from deflection board to neck board
      on neck board:
         R503 (open)
         R513 (wrong value)
         R520 (wrong value; was 22)
         R530 (open)
         Q501 (bad or base shorted to emitter)
         broken wire at R513
         jumper from R511 to R513 missing
   Only green; check:
      on neck board:
         Q503 (reversed or wired wrong)
   Green too bright; check:
      on neck board:
         Q501 (collector shorted to emitter)
   No green + blue is red; check:
      on neck board:
         R500 (shorted to R529 or shorted to R502)
   Green is red; check:
      on neck board:
         R502 (shorted to R500)
   Green does not turn off when dimmed all the way; check:
      on neck board:
         R512 (shorted to nearby wire or connecting wires wrong)
         R519 (connecting wires wrong)
         R520 (open)
         Q501 (reversed, open, shorted, or broken wire to base)
   No blue; check:
      on deflection board:
         D803 (bad) or neck board connector wired wrong)
      on neck board:
         R504 (wrong value)
         R515 (open or wrong value or broken wire or swapped with R505)
   Only blue; check:
      on deflection board:
         red lead in neck board connector broken
   Blue does not turn off when dimmed all the way; check:
      on neck board:
         R504 (open)
         R521 (open)
         R522 (open)
         R529 (open)
         Q502 (reversed, emitter open, or shorted to nearby component)

The following section lists problems with the High Voltage board.

The image is extremely shaky and unstable and lines that should be
straight have periodic wiggles along their length that make them look
like an EKG (the distortion is sort of like when you watch TV with a bad
antennae and lines "walk" around on the screen):  Replace C901, C902,
and/or C905 in the HV supply.  If of these is bad then the rest of the
electrolytic capacitors are probably in pretty poor condition too, so I
generally replace all of them.  Make sure the replacements are rated at
as least as many "working volts DC" WVDC and have as least as many
micro-Farads.  It doesn't hurt to replace a 22uF @ 50V capacitor with a
50uf @ 100V if that is all you have around.  More Voltage capacity is
equal or better but it is best to keep the capacitance the same if you
can.  Also when ordering and replacing these, be aware that they are
polarized and not idiot-proof; be sure to put them in the circuit so
that they are oriented properly.  The casing will clearly indicate
either the negative or the positive terminal (but typically not both)
and the industry convention is for the positive lead of the capacitor to
be longer than the negative lead.  Be aware that P329 has an extra
capacitor (C22) that may not be shown in your manual; its value is 10uf
at 63V.

If the picture is overly bright and all parts check out OK, look for a
broken circuit board trace between pin 6 of the high voltage transformer
and the anode of diode D901.  This trace is prone to breaking open.  It
is probably easier to just add a jumper and see if it solves the problem
or else check the connection (with board removed) with a meter to make
sure it is a short.

If R925, R919, and R917 are smoked, check:
   Q905 (shorted; T901 primary may be shorted, too)
If R901, R907, R903, are smoked and Q902 and ZD901 are shorted, check:
   Q901 (reversed)
If you are blowing the top off Q901, check:
   R902 (open)
   Q900 (inserted or wired wrong; if emitter shorted to base then Q901,
         Q902, and ZD901 get fried)
   Q901 (shorted)
   Q902 (shorted)
   ZD901 (shorted)
If you are blowing the top off Q902, check:
   Q901 (reversed)
If R901 and R907 are smoking, check:
   Q902 (shorted)
   Q906 (red and white leads interchanged)
If just R901 smokes, check:
   Q906 (inserted wrong)
   Q900 (missing spacer or black lead open)
If R903 smokes, check:
   Q900 (shorted; will short ZD901, Q901, and Q902, too)
IF R904 smokes, check:
   Q902 (shorted)
If R907 smokes, check:
   C902 (reversed)
   broken wire near R902
If R908 smokes, check:
   Q900 (white and black leads interchanged)
If R912 smokes, check:
   C910 (reversed)
   D901 (wrong value; perhaps ZD902)
If R917 smokes, check:
   Q905 (reversed)
If R920 smokes, check:
   C913 (bad; this can damage T901, too)

No High Voltage (HV); you don't hear the crackling sound when you first
turn the monitor on:  Check the transistors in the HV unit as described
earlier.  The ones I've seen fail most often are Q903, Q902, and Q901
though they are all suspect.  These transistors will usually have cracks
in the casing if they are bad so look closely at them.  If all this
stuff is OK, look at the electrolytic capacitors (they are the big
cylindrical tube-like parts and are usually blue in color) in the
circuit.  They come in two "types":  +---+
             +---+                   |   |
axial-lead --|   |-- and radial-lead |   |
             +---+                   +---+
                                      | |

One quick errata:  The parts list in Figure 15 of TM-183 lists all
capacitors as fixed axial-lead when in reality only C905 is; the others
are all radial-lead.  These are designed to burst open when they fail
due to overburdening (but they sometimes don't) so as to be obvious to
repairpersons.  The top (for radial-leads) or the side (for axial-leads)
will be open and some of the "guts" will be hanging out.  When some
capacitors go bad, they sometimes take the final output resistors R901
and/or R907 with them (but the resistors will look perfectly OK unless
you check them with a meter).  Also check to make sure that connector
J901 inside the HV unit is intact; on person reported that the plastic
in his disintegrated on the inside and the wires came loose.  If these
are OK, check the following:
   waveform at IC901 outputs; if missing check:
      R914 and/or R927 (wrong value)
      R916 (broken wire)
   waveform at Q906; if missing, check:
      R926 (open)
      Q906 (white wire open)
      Q905 (emitter open)
   waveform at Q905; if collector wrong, check:
      Q906 (broken black lead or broken wire at emitter)
   waveform at R921; if wrong, check:
      Q906 (white and black leads interchanged at socket)
   IC901; if no input voltages then check:
      Q900 (red and black leads reversed)
      ZD901 (check voltage drop)
      ZD900 (shorted)
   IC901; if input voltages present then check:
      R914 (may be open; will cause waveform at C911 to not be X1K range)
   C911 (open)
   C915 (open)
   C916 (open)
   R901 (open)
   R904 (open)
   R905 (open)
   R913 (open)
   R923 (open)
   R924 (open)
   Q900 (shorted; +25 line is grounded by this)
   Q904 (reversed, open, or missing)
   Q905 (reversed or collector wire broken)
   IC901 (defective, reversed, or unseated pins)
   T901 (pins unseated or primary winding shorted)
   Broken wire at R913
   Broken wire at R919
   Broken wire at base or collector of Q905
   Broken wires or pins at P900
   White wire disconnected at Q900
   Red wire disconnected at Q906
If you are also blowing any fuses, check:
   C910 (reversed)
   R907 (open)
   R913 (shorted)
   D902 (wrong value)
   Red and white wires interchanged at Q906

F600 blows immediately on powerup: Replace R612 if open.

Blooming/"weak" brightness/Low HV:  Most of you don't have a HV probe
but the most common symptom of low HV is that the screen looks as though
you are looking at the center through a magnifying glass.  This visual
symptom is known as "blooming".  I've seen several times where ZD902
(150 volt Zener diode) goes bad and the HV drops from 19.5 kilovolts to
around 10 kV.  It's kind of like the electron beam moves slower with
less HV giving the deflection magnets on the yoke more time to deflect
the beam (but what is really happening is that there is not enough HV to
strip all of the electrons off of the phosphor coating which causes the
screen to develop a negative charge which then deflects new electrons
which are expected to be hitting a screen with no charge on it).  A new
ZD902 and everything is better.  NTE5100A is a common modern day
replacement for this part.  If ZD902 is OK, check the following:
   R915 (open)
   R922 (open or wrong value)
   Q900 (emitter pin open)
   Q902 (bad)
   Q906; white and black leads reversed (scope pattern is wrong)
   ZD901 (shorted)
   IC901; if scope output is a little high, replace IC901
   P900 (ribbon pin #7 broken)

High voltage range wrong (normal is 16-24 kV); range is:
   ??.?-12.0; Q902 (reversed).
    7.0-10.0; ZD902 (bad)
    7.0-17.0; ZD902 (bad)
    7.0-22.0; Q903 (bad)
    9.0-18.0; ZD902 (bad)
   11.0-22.0; ZD902 (bad)
   15.0-18.0; ZD901 (wrong value)
   16.0-19.0; ZD902 (bad)
   18.0-27.0; ZD902 (bad)
   19.0-27.0; R912 (wrong value)
   21.7-30.5; C916 (open)
   28.0-20.0; C916 (bad)

High voltage control has no effect; value is always:
   7.4;  Q903 (collector wire shorted to HV control wore)
   7.7;  Q903 (reversed or base and collector interchanged)
   8.0;  Q903 (reversed or base and collector interchanged)
   11.0; Q902 (reversed)
   12.0; IC901 internal frequency changed by ZD902 (bad)
   13.0; Q902 (reversed) or C920 (open) or ZD902 (bad)
   16.0; Q900 (black and white wires interchanged)
   17.0; ZD901 (shorted)
   18.0; ZD902 (bad)
   22.0; Q900 (reversed or black and white wires interchanged)
   24.0; R912 (open) or Q900 (black and white wires interchanged)
   27.0; R902 (open; this burns Q901, Q902, and ZD901)
   28.0; broken wire at Q902
   30.0; R915 (open)
   32.0; ZD901 (bad) or R918 (open) or Q902 (collector lead open)

Here is a really strange one about a problem with the tube itself!

Focus starts out sharp but slowly gets fuzzy and then suddenly snaps
back into clear focus (repeat every 10 seconds; eventually will stay out
of focus all the time):  I didn't see the problem until I extended the
wiring harness out of the back of the machine so the monitor was sitting
on a stand, because there *was* arcing occurring, but it was *inside*
the picture tube socket.  There's a white, cubic lump attached to the
end of the neck (where the neck board attaches) where all the pins are
and I could see a faint glow out of it when the monitor freaked.  The
focus line from the HV power supply connects to the pin nearest the
cube.  Inside of it, a sort of spark gap is implemented by running the
focus wire under and in contact with a small metal plate (the wire
eventually connects to the socket pin).  A second formed wire is
suspended above the metal plate with the point of a V bend in the wire
forming a spark gap with the metal plate; this formed wire is connected
to chassis ground.  Its purpose is to form a spark gap with certain pins
in the socket; the intent is to prevent damage to the gun of the CRT
during power down.  In my case, the focus wire had lost good contact
with the socket pin, and some internal arcing of some sort appeared to
have released the metal plate from where the plastic housing was
supposed to retain it, causing the spark gap to become too small.  So it
appears one problem led to another.  The connection to the focus pin of
the picture tube socket had become intermittent.  Some arcing caused the
built in spark gap to come apart.  A similar problem with the same
symptoms can develop causing a dead short to ground of the focus
electrode.  Within the socket, there is a plate in the back of the
socket which is grounded.  If any moisture or conductive crud gets in
there, you can get a low resistance path between the grounded plate and
the focus pin.  To fix it, you have to desolder the socket and break it
open.  The socket simply pries apart but it was originally staked, so
don't be alarmed if you see small pieces of plastic flying off when you
pry the sucker open.  I found it went together tightly enough that I
wasn't concerned about it falling apart but you could use a touch of
glue just to be sure.  I soldered the metal piece to the focus wire,
placed it back in its retaining channel, cleaned out the gap area and
soldered the socket back in place.  The part that comes off the bottom
of the socket to gain access to the internals touches the PC board when
the socket is installed, and is retained just fine when the socket is in
place without gluing.

All the above is assuming you just plug the game in and it doesn't work.
If you happen to be playing the game at the time it fails, you have a
little more information to go on.  If you hear a loud bang like a
firecracker, then check the capacitors on the HV board first because
they can be loud when they burst.  If you see a little bit of smoke
inside the cabinet and smell a hint of "electrical smell", then check
the fuses first.  If you see a ton of smoke inside the cabinet, then
check the large transistors on the chassis first.  If you start losing
quadrants of your screen intermittently than I would advise replacing
the corresponding transistor before it fails because it can take other
components (usually fuses) with it when it goes altogether.  The same
advice goes for the blooming caused by ZD902.

Now some things besides the monitor itself.  Tempest is harder on this
monitor than the other Atari vector games.  The attract mode that
displays "TEMPEST" (often burned right into the phosphors) really
stresses the monitor.  For Tempest, I like to do what Atari did when
they offered the Major Havoc conversion.  Add a fan to the back door of
the game.  I try to find a small cooling fan that just moves a small
amount of air (not one that howls).  You have to cut a hole in the back
door and position it so it directs air at the deflection board.  I
usually connect the power for the fan to the wires that head up to the
fluorescent light and put a connector in so that you can still remove
the back door (with the fan mounted on it) without it hanging on the
wires to the fan.

If you would like to greatly reduce your chances of experiencing a
monitor failure in your Tempest machine, you may want to "shrink" the
screen in both axes using the X and Y "SIZE" pots on the game board.  I
also have heard Tempest was bad, because it draws a diagonal retrace
line (Z/brightness off) from the bottom left corner to top right corner
during the attract mode.  There was supposed to be a ROM fix, which took
this line out and really helped the transistors but I've never seen it.
I could probably buy it, as it was supposed to have been pushed for by a
local operator.

All of this has assumed that you had a good logic board in the game and
the monitor was receiving the vector info.  If the spot killer stays on
and the monitor seems OK verify the presence of the X and Y signals by
measuring between ground and pin 7 of the big white connector for the X
signal and pin 8 for the Y signal.  This is an AC signal and if either
is missing the spot killer circuit is just doing it's job and saving the
tube's phosphors.

You might also want to check that you don't have static analog data
(voltage) saturating your transistors.  To check this, set your
multi-meter on the DC voltage scale and measure the voltage on the lead
of R600 and R700 which are connected to the yellow and orange wires,
respectively.  The correct voltage should average out to about 0 volts
DC but will fluctuate (both positive and negative) because of the
changing deflection signal.  If the measured voltage is constant
(between 5 and 15 volts positive or negative DC) then check the X and Y
amplifiers on the game board.

Now that you have a working monitor (and game), it is time to fine tune
your picture.  Before making any adjustments, turn your game on and let
it warm up for at least 10 minutes.  R918 is the HV adjust and my advice
is that unless you have a HV probe, don't mess with it.  If you have a
probe, set the HV for 19.5 kV with zero beam current (i.e. with the
game boards disconnected from the machine so that no input signals are
being supplied).

Some HV supplies (P329) have a circuit called the HV over-voltage
protection circuit.  It monitors the voltage of the focus assembly in
the secondary circuit of T900.  If the high-voltage at the anode of the
picture tube increases beyond the threshold set by H.V.  TRIP adjustment
R930, this circuit shuts off the timer of IC901 and LED D903 turns on to
indicate the over-voltage condition.  Presumably, this was added to help
discourage Tempest from eating HV transformers as it is prone to do
since they are by far the most expensive component in the game.  Adjust
R930 so that it is just beyond the point where LED D903 lights (so that
the LED is off).

NOTE:  The following adjustments are a 2 person job (unless you are very
handy with mirrors) because it is nearly impossible to view the screen
and turn the pots at the same time.  When adjusting your monitor, all
adjustments should be made in the order as presented below as many of
the adjustments have effects on other qualities and will cause you to
have to go back and redo them if you change the order.

On the outside of the HV assembly are focus and brightness adjustments.
Adjust the focus until the picture is sharp then adjust the brightness
just under the point where the dot in the center starts to show or just
under the point where you can see the connecting lines between objects.
Be careful to not get carried away with the brightness as you can do
permanent damage to the phosphors.

The manuals don't talk much about adjusting the positioning and size of
your screen but that is easy to do.  There are small potentiometers on
the game board that are clearly labeled which control X and Y centering
as well as X and Y size.

The following adjustments refer to the 8 tiny blue and/or black
potentiometers found on the large game board towards the back on a
Tempest machine.  If your lines are not meeting at the "joints" properly
or your text and numbers aren't lined up properly on the statistics
screen then you need to make these adjustments.  This information is
directly from the Tempest schematic diagram supplements (sheet 2, side
B, 3rd printing) so locations/numbering/labeling of the pots may be
different for other vector games but the instructions should be
relatively portable...

================================================================================

[NOTE:  Atari did copyright these documents and they are clearly marked
with a copyright symbol.]

[NOTE:  All of the following controls exist in the Vector Generator
section of the game PCB; THEY ARE NOT IN THE MONITOR!]

+------+        +------+        +------+
|/\/\/\|        |  |   |        |  |   |
|\/\/\/|        |  |   |        |  |   |
|/\/\/\|        |  |   |        |  |   |
|\/\/\/|        |---   |        |--+---|
|/\/\/\|        | -----|        |  |   |
|01..YZ|        |   |  |        |  |   |
|\/\/\/|        |   |  |        |  |   |
+------+        +------+        +------+
screen I        screen J        screen K

Enter self-test and advance screens to the diagonal crosshatch pattern
[the one with the line of numbers and letters at the bottom; screen I].

Adjust "CENTER" pots:  Adjust X-CENTER (R147) and Y-CENTER (R167) so
that the pattern is located at the middle of the screen.

Adjust "SIZE" pots:  Adjust X-SIZE (R150) and Y-SIZE (R168) so that the
pattern exactly covers the whole visible screen.

Adjust the "BIP" pots ["BIP" stands for "Bipolar" but I don't know what
that means...]:  Adjust the X-BIP (R118) and Y-BIP (R117) so that the
corners of the diagonal lines rest exactly on the sides of the outer
rectangle.  [NOTE:  It may be easier to advance to the screen with the
single large cross-hair on it to make the BIP adjustments; just make
sure the lines meet at exactly the center.  Using this screen, you
should try to make screen J look like screen K.  Be careful when joining
the lines in the middle that you don't overlap; it is *very* hard to
notice this.  I suggest you make a big gap (go the wrong way) and then
converge until the 2 segments just touch.  Screens J, and K were added
by me and are not shown in the original document.]

Adjust the "LIN" pots:  Adjust the X-LINEAR (R169) and Y-LINEAR (R165)
so that the diagonal lines are straight.  Since the "LIN" pots change
the size of the displayed picture on the screen, you may have to
readjust the "SIZE" pots in order to get the correct adjustment.

================================================================================

Here is a summary of the white balance adjustment sections of TM-183.
This is paraphrased and abridged since the information was spread out
over many boring pages.  You should make these adjustments before you
adjust the purity and convergence.  Do not do it in reverse order
because color changes do slightly impact those other adjustments.

================================================================================

Flip the test switch inside the coin door on the top near the hinge
(some games may have the self-test switch mounted in a different area
such as on a plate near the top of the coin box).  Tempest requires you
to rotate the spinner until the prompt reads "Press Fire and Zap for
Self-Test".  Other games may have similar requirements to get to the
self test screens or they may take you directly to them automatically.
Do whatever is required to enter the self test screens.

Advance the screens with the slam (a.k.a. "tilt") leaf switch (this is
typically inside the coin door below the lock) until you get to the
diagonal crosshatch pattern screen (see "screen I" in the next section).
For Tempest this should be the 1st screen.

Turn the focus control (one of the 2 white knobs on the HV unit) until
you get the optimum screen sharpness possible.  Your goal is the best
character appearance without appreciable fuzziness.

Advance the screens until you get to one showing 7 groups of colored
bars of various intensities.  For Tempest this should be the 5th screen.

Turn all the potentiometers on the neck PCB to the full clockwise
position.  Turn the brightness control (the other white knob on the HV
unit) so that only 5 lines are visible and 6th one is completely
invisible.  Adjust the red, green, and blue bias potentiometers (the
black ones) until the 5th line from the right is pure white without any
hint of color in it (the 5th line is the dimmest one and color bias
abnormalities are most visible at lower brightness levels; the goal is
to get all 5 lines to be completely white).  Adjust the red, green, and
blue drive potentiometers (the white ones) until the 1st line on the
right is pure white.  Repeat the bias adjustment if the 5th line from
the right is no longer pure white.

================================================================================

As far as adjusting purity (red gun hits red phosphors only, green gun
hits green, etc.)  and convergence (red, green, and blue guns hit
adjacent dots to make white instead of separate colors), that is a whole
different subject and the manual does a decent job of walking you
through the procedure.

================================================================================

Here is the associated information from the Wells-Gardner Service Manual:

COLOR PURITY

For best results, it is recommended that purity adjustment be made with
display unit facing west or east.  The display unit must have been
operating 15 minutes or more prior to this procedure.

With yoke on CRT neck, set convergence assembly on CRT neck with the
center line (of Purity Adjustment Magnet) over gap between grids No. 3
and No. 4.  The convergence assembly consists of 3 sets of ring magnets
with tabs (Figure 6).

-------------------             +-----------+
  \             /       /-+     |===========| <- Purity Adj.
 ////////////////======|  |     |===========| <- Red/Blue Adj. (4 pole)
  --------------        \-+     |===========| <- Red/Blue
    |  +--+  |                +-+----II-----+    on Green Adj. (6 pole)
    |+-|  |-+|                +-+-----------+
    || |  | || <- Grid No. 4      TOP VIEW
    |+-|  |-+|                /|\
    |  |  |  | <- last gap     |    Concentric Convergence
    |+-|  |-+|                 s    Assembly shown in zero
    || |  | || <- Grid No. 3   c    correction position.
    ||_|  |_||                 r
    || |  | || <- Grid No. 2   e  REAR VIEW
    || |  | ||                 w     __
    |+-|  |-+|                 |    /  \
    |  |  |  | <- first gap    |    |++| <- Tabs of ring magnets all
    |+-|  |-+|                \|/  _||||_   in vertical position.
    ||-|  |-|| <- Grid No. 1      / ____ \
    ||=|  |=||                ===/ /    \ \
    | \+--+/ |                 ~| |      | |
     \ |  | /                  ~| |      | |
      \|  |/                  -~-\ \____/ /
      ======                   ~  \______/
      ||||||                         II

-----------------------------
          FIGURE 6

Tabs of the 3 magnetic ring-pairs are to be in a vertical position which
will produce a zero-correction state and facilitate adjustments.
(Figure 6).

Connect a generator or game (self-test mode) which can generate a
crosshatch patter of red, green and blue inependently and in combination
of colors.  Refer to "INTERFACE BOARD ADJUSTMENTS" for input signal
level and pattern size.

With a green crosshatch pattern, pull the deflection yoke backward as
far as it will go.  The center vertical portion will be green.  If green
is not horizontally centered between other colors, move the 2 purity
magnets with respect to each other in order to center green crosshatch
on the screen.

Push deflection yoke forward gradually, until crosshatch is a uniform
green (pur in color) across the entire pattern.  The deflection yoke
should be secured in place.

Both red and blue colors are to be checked for uniformity and true
color.  Reposition the deflection yoke, if necessary, to obtain optimum
purity of all colors.  Tighten clamp to secure deflection yoke.

STATIC CONVERGENCE ADJUSTMENT

4-Pole Magnets and 6-Pole Magnets are for static convergence.

1.  A crosshatch signal should be connected to the monitor.
2.  A pair of 4-Pole Convergence Magnets is provided and adjusted to
    converfe the blue and read beams (Figure 6).  When the Pole opens to
    the left and right 45 degrees symmetrically, the magnetic field
    maximizes.  Red and blue beams move to the left and right.
    Variation of the angle between the tabs adjusts the convergence of
    red and blue vertical lines.
3.  When both 4-Pole Convergence Magnet Tabs are rotated as a pair, the
    convergence of the red and blue horizontal lines is adjusted.
4.  A pair of 6-Pole Convergence Magnets is also provided and adjusted
    to converge the magenta (red + blue) to green beams (Figure 6).
    When the Pole opens to the left and the right 30 degrees
    symmetrically, the magnetic field is maximized.  Red and blue beams
    both move to the left and right.  Variation of the opening angle
    adjusts the convergence of magenta to green vertical lines.
5.  When both 6-Pole Convergence Magnet Tabs are rotated as a pair, the
    convergence of magenta to green horizontal lines is adjusted.

ADJUSTMENT OF DYNAMIC CONVERGENCE (Figures 7, 8 and 9)

[NOTE:  This text refers to a monitor oriented in the proper horizontal
position.  Some games such as Tempest use the monitor rotated 90 degrees
into the vertical poisition.]

1.  Feed crosshatch signal to the monitor.
2.  Insert a wedge temporarily and fix the Deflection Yoke so as to
    obtain the best circumference (Figures 8a through 9b).  NOTE:  The
    wedges may need to be moved during adjustments.
3.  Insert three rubber wedges to the position as shown in figure 7 to
    obtain the best circumference convergence.

NOTE:
1.  Tilting the angle of the yoke up and down adjusts the crossover of
    both vertical and horizontal red and blue lines (Figures 8a and 8b).
2.  Tilting the angle of the yoke sideways adjusts the parallel
    convergence of both horizontal and vertical lines at the edges of
    the screen (Figures 9a and 9b).
3.  Use three rubber wedges (tapered rubber wedges are used for thie
    purpose.)
4.  The position of each rubber wedge is shown in Figure 7.
5.  Do NOT force the permanenet wedges in.  They are to be inserted
    until they just make contact with the yoke - after the yoke ahs been
    positioned.
6.  Fix the three permanent rubber wedges with chloroprene rubber
    adhesive.
7.  After the adhesive has dried enough to hold the wedges in place,
    carefully remove the temporarily installed wedge.
          _
         | | <---------- Temporarily Installed Wedge
      ___|_|___
 /\  /_________\  /\
/  \//         \\/  \ <- Rubber Wedge
\  //           \\  /    (60 degrees from Temporary)
 \// +---------+ \\/
 //  |   ___   |  \\
||   |  /   \ <--------- CRT Neck
||   | |     | |   ||
||   |  \___/  |   ||
 \\  |         |  //
  \\ +---------+<------- Deflection Yoke
   \\           //
    \\_________//
     \_________/
         | |
         |_|
     FIGURE 7 (Rear View)

+---------------------------+
|        B    G    R        |  Insert rubber wedge
|         \   |   /         |  from upper (right for
|          \  |  /          |  Tempest) side
|  R___     \ | /     ___B  |      |
|      ---___\|/___---      | S V  v
|  G----------*----------G  | I I    / \    /
|      ___---/|\---___      | D E   /   \  /
|  B---     / | \     ---R  | E W  / DY  \/
|          /  |  \          |     /      /-----+
|         /   |   \         |     ------/------+
|        R    G    B        |          /
+---------------------------+         /
          FIGURE 8A

+---------------------------+         \
|        R    G    B        |          \
|         \   |   /         |     ------\------+
|          \  |  /          |     \      \-----+
|  B___     \ | /     ___R  | S V  \ DY  /\
|      ---___\|/___---      | I I   \   /  \
|  G----------*----------G  | D E    \ /    \
|      ___---/|\---___      | E W  ^
|  R---     / | \     ---B  |      |
|          /  |  \          |  Insert rubber wedge
|         /   |   \         |  from lower (left for
|        B    G    R        |  Tempest) side
+---------------------------+
          FIGURE 8B

+---------------------------+     TOP VIEW
|+-------------------------+|        /\
||+-----------------------+||       /  \  /
|||                       |||      / DX \/
|||                       ||| +-> /     /|
|||                       |G| |   -----/||
|||                       B|R |       / ||
|||                       ||| |         ++
|||                       ||| |
|||                       |||  Insert rubber wedge
||+-----------------------+||  from left (top for
|+-------------------------+|  Tempest) side
+---------------------------+
          FIGURE 9A

+---------------------------+     TOP VIEW
|+-------------------------+|        /\
||+-----------------------+||    \  /  \
|||                       |||     \/ DX \
|||                       |||     |\     \ <-+
|||                       |G|     ||\-----   |
|||                       R|B     || \       |
|||                       |||     ++         |
|||                       |||                |
|||                       |||  Insert rubber wedge
||+-----------------------+||  from right (bottom
|+-------------------------+|  for Tempest) side
+---------------------------+
          FIGURE 9B

================================================================================

Now that you have your monitor repaired and adjusted, I'll discuss the
variety of ways that exist to make your monitor (or rather, your
deflection board) more robust and hopefully reduce or eliminate future
failures.

Here is some text from the Major Havoc conversion kit installation
instructions (TM-268).  It describes the Atari sanctioned upgrades and
includes instructions for converting all Wells-Gardner P314 Deflection
Board PCB variations to Atari's "official" upgrade.  Thanks to Tony
Jones (ant@palm.cray.com) for sending this to me.

================================================================================

[NOTE:  Atari did copyright these documents and they are clearly marked
with a copyright symbol.]

Major Havoc Installation Instructions TM-268

H. MODIFY THE WELLS-GARDNER DEFLECTION PCB
------------------------------------------

          +------------------------ NOTE ------------------------+
          | The following procedure applies to those Space Duel, |
          | Gravitar, and Black Widow games that used a Wells-   |
          | Gardner display.  If your game has an Amplifone      |
          | display, proceed to I. Modify the Amplifone          |
          | Deflection PCB [found earlier in this document].     |
          +------------------------------------------------------+

Four versions of the Wells-Gardner display were used in the
Space Duel, Gravitar, [Tempest,] and Black Widow games.  Perform the
preliminary procedure for all versions of the display, then refer to
Table 3 to determine which version of the four displays was installed in
your game and perform the additional procedure for that version.

          +---------------------- CAUTION! ----------------------+
          | When soldering components to the display circuitry,  |
          | apply just enough heat to provide a proper electri-  |
          | cal connection.  Excessive heat can damage the       |
          | semiconductor material.                              |
          +------------------------------------------------------+

Preliminary Procedure
---------------------

Perform the following procedure to modify the Deflection PCB (see
Figures 6 and 7).

   1.  Set the display on a clean work surface.
   2.  Disconnect the 15-pin Molex connector from the mounting bracket
       on the display chassis and the harness connectors from the
       Deflection PCB and the Neck PCB.
   3.  Use a 1/4-inch hex driver to remove the two screws securing the
       Deflection PCB to the display chassis [NOTE:  there are holes for
       2 more screws in the remaining (rear) 2 corners of the board
       which some users decided to fill; if the board won't come out,
       check for this]
   4.  Remove the Deflection PCB from the display.
   5.  Connect two type-1N754A Zener diodes together, anode to anode,
       as shown in Figure 6.  Use a soldering iron to solder the two
       anode leads together.

                 Solder Here
                     |
CATHODE +-+------+  \|/   +------+-+ CATHODE
--------+ |1N75#A+--------+1N75#A| +--------
        +-+------+ ANODES +------+-+

        ----|<----        ---->|----

Figure 6 IN754A and 1N756A Zener-Diode Connections

[Figure 7, entitled "Modifying the Wells-Gardner Deflection PCB",
showing 2 half scale pictures of the solder side of the Deflection PCB,
has been omitted for obvious reasons.  It does not show anything that
cannot be derived from the included text; it was merely a "visual aid".
The top picture is the P327/339 design and the bottom is P314.]

   6.  Connect two type-1N756A Zener diodes together and solder as
       described in step 5.
   7.  Examine the soldered side of the Deflection PCB removed from the
       display and determine which of the two PCBs shown in Figure 7
       matches your PCB.
   8.  On the component side of the Deflection PCB, locate the yellow
       wire (top right side of the PCB).
   9.  Solder one cathode lead of the two type-1N754A Zener diodes
       (soldered together in step 5) to the yellow lead on the soldered
       side of the PCB as shown in the appropriate illustration in
       Figure 7.
  10.  Solder the other cathode lead of the two type-1N754A Zener diodes
       to ground as shown on the appropriate illustration in Figure 7.
  11.  On the component side of the Deflection PCB, locate the orange
       wire (near top center of the PCB).
  12.  Solder one cathode lead of the two type-1N756A Zener diodes
       (soldered together in step 6) to the orange lead on the soldered
       side of the PCB as shown on the appropriate illustration in
       Figure 7.
  13.  Solder the other cathode lead of the two type-1N756A Zener diodes
       to ground as shown on the appropriate illustration in Figure 7.
  14.  On the component side of the Deflection PCB, locate connector
       P600 (right center of the PCB).
  15.  Solder the cathode lead of a type-1N4002 diode to pin 1 and the
       anode lead to pin 4 of connector P600 on the soldered side of the
       PCB as shown on the appropriate illustration in Figure 7.
  16.  Solder the cathode lead of a type-1N4002 diode to pin 5 and the
       anode lead to pin 7 of connector P600 on the soldered side of the
       PCB as shown on the appropriate illustration in Figure 7.
  17.  On the component side of the Deflection PCB, locate connector
       P700 (left center of the PCB).
  18.  Solder the cathode lead of a type-1N4002 diode to pin 1 and the
       anode lead to pin 4 of connector P700 on the soldered side of the
       PCB as shown on the appropriate illustration in Figure 7.
  19.  Solder the cathode lead of a type-1N4002 diode to pin 5 and the
       anode lead to pin 7 of connector P700 on the soldered side of the
       PCB as shown on the appropriate illustration in Figure 7.
  20.  Refer to Table 3 to determine which of the four versions of the
       display has been installed in your Tempest game.

Table 3 Display Versions
----------------------------------------------------------------------
                    Determine                                Procedure
----------------------------------------------------------------------
Deflection PCB has two large, black, tubular capacitors,     Version 1
C804 and C805, installed below top center of PCB.
[NOTE:  These are 1" long and .25" in diameter and are
radial lead type; I guess as far as PCB components go,
they could be considered large but as far as
electrolytics go, they are rather small.  As far as I
know, these are present only on versions P327 and P339
of the Deflection PCB (which have the Input Protection
Circuit redesigned into the board).  This question could
probably more easily be phrased, "Is your board labeled
P327 or P339." The fact that they chose not to word the
question this way implies that there are some board
redesigns which were labeled P314 instead of P327.  The
proceeding 3 descriptions refer only to (most but
perhaps not all of) the various flavors of the P314
version of the Deflection PCB (i.e. not P327 nor P339).]

Input Protection Circuit PCB is installed (piggyback)        Version 2
WITH A 1K Ohm, +/-5%, 1/4 W RESISTOR CONNECTED BETWEEN
THE INPUT PROTECTION CIRCUIT PCB AND THE DEFLECTION PCB.
[NOTE: I have documented this PCB immediately following
this article.]

Input Protection Circuit PCB is installed (piggyback)        Version 3
BUT DOES NOT HAVE A RESISTOR CONNECTED BETWEEN
THE INPUT PROTECTION CIRCUIT PCB AND THE DEFLECTION PCB.

Deflection PCB DOES NOT HAVE CAPACITORS C804 AND C805        Version 4
(BELOW TOP CENTER OF PCB) OR AN INPUT PROTECTION
CIRCUIT PCB INSTALLED.
----------------------------------------------------------------------

  21.  Perform the procedure as follows for the appropriate version of
       the display determined from Table 3.  (Refer to the display
       manual, TM-183, for component and connector locations).

          +------------------------ NOTE ------------------------+
          | The 30Kohm, 1/4W resistor supplied in the kit is     |
          | used only for Version 1 of the Wells-Gardner dis-    |
          | play.                                                |
          +------------------------------------------------------+

Version 1
---------

Perform the following procedure for Version 1 of the Wells-Gardner display.

   1.  Verify that the Preliminary Procedure has been performed.
   2.  Use a soldering iron to remove resistor R811 and replace it
       with the 30Kohm, 1/4W resistor supplied in the kit.
   3.  Use a 1/4-inch hex driver to secure the modified Deflection PCB
       to the display chassis.

          +------------------ CAUTION! ------------------+
          | Make certain that the harness from Q705 and  |
          | Q706 is connected to P700 and not P100.      |
          +----------------------------------------------+

   4.  Connect the harnesses to the appropriate Deflection PCB
       connectors.

Version 2
---------

Perform the following procedure for Version 2 of the Wells-Gardner display.

   1.  Verify that the Preliminary Procedure has been performed.
   2.  Use a 1/4-inch hex driver to secure the modified Deflection PCB
       to the display chassis.

          +------------------ CAUTION! ------------------+
          | Make certain that the harness from Q705 and  |
          | Q706 is connected to P700 and not P100.      |
          +----------------------------------------------+

   3.  Connect the harnesses to the appropriate Deflection PCB
       connectors.

Version 3
---------

Perform the following procedure for Version 3 of the Wells-Gardner display.

   1.  Verify that the Preliminary Procedure has been performed.
   2.  Locate the wire connected to resistor R1 (22K ohm) and the
       collectors of transistors Q1 and Q3 (type 2N3904) on the Input
       Protection Circuit PCB and the point shown in Figure 7 on the
       Deflection PCB.
   3.  Use a wire cutter to cut the wire, located in step 2, half-way
       between the two PCBs.
   4.  Use a soldering iron to solder a 1K Ohm, +/-5%, 1/4 W resistor
       (not included in the kit) between the two ends of the wire cut in
       step 3.
   5.  Use a 1/4-inch hex driver to secure the modified Deflection PCB
       to the display chassis.

          +------------------ CAUTION! ------------------+
          | Make certain that the harness from Q705 and  |
          | Q706 is connected to P700 and not P100.      |
          +----------------------------------------------+

   6.  Connect the harnesses to the appropriate Deflection PCB
       connectors.

Version 4
---------

Perform the following procedure for Version 4 of the Wells-Gardner display.

          +------------------------ NOTE ------------------------+
          | This version of the display requires that an Input   |
          | Protection Circuit PCB assembly be installed on the  |
          | Deflection PCB as part of the display modification   |
          | procedure. This PCB assembly is not included in the  |
          | kit.  However, to obtain the Input Protection Cir-   |
          | ciut PCB assembly, use the order form at the back    |
          | of this document.                                    |
          +------------------------------------------------------+

   1.  Verify that the Preliminary Procedure has been performed.
   2.  Install the Input Protection Circuit PCB to the Deflection PCB as
       described in the instructions supplied with the Input Protection
       Circuit PCB assembly.
   3.  Use a 1/4-inch hex driver to secure the modified Deflection PCB
       to the display chassis.

          +------------------ CAUTION! ------------------+
          | Make certain that the harness from Q705 and  |
          | Q706 is connected to P700 and not P100.      |
          +----------------------------------------------+

   4.  Connect the harnesses to the appropriate Deflection PCB
       connectors.

================================================================================

The following are hardware modifications you can make to the deflection
board to improve its reliability.  I have seen all in action and can
verify them to be "non-lethal" modifications but cannot really attest to
their usefulness since I don't run my Tempest under stress.  I would
advise that you only implement 1 of them unless you are sure they are
compatible (I am not).  If anybody knows if any are compatible (or not),
let me know.  For now, I am listing them as mutually-exclusive; mix at
your own risk.  I'd take the time and hassle to do the first one even
though it is a lot more work.

The Input Protection Circuit did not include any background in the kit
so here are those details which I found on page 3 of the May 1982 issue
of Star*Tech Journal:

================================================================================

NEW INPUT PROTECTION CIRCUIT FOR WELLS-GARDNER COLOR X-Y DISPLAY

This display contains an additional small printed-circuit board (PCB).
The PCB is mounted in "piggy-back" style on top of the Deflection PCB.

The input protection board was added to protect the fuses in the display
from damaging input voltage conditions.  Without this board, the display
fuses might blow in the event of an intermittent or long-term game PCB
failure.  With this board, the screen will momentarily go blank if the
average X- or Y-axis voltage(s) exceed a certain level.  The screen then
automatically recovers for normal game play and earning when the
voltage(s) return to normal.

If this display is used in Atari "Tempest" games, be sure to correctly
adjust the X and Y SIZE and CTR video pots on the "Tempest" Analog
Vector-Generator (main) PCB.  The instructions for the adjustments are
printed on the "Tempest" schematics - Sheet 2, Side B - 3rd printing or
later [and can also be found in this document].  Improper adjustment may
cause the screen to go blank during normal game play.

================================================================================

Now onto the actual Atari document about the IPC.

================================================================================

[NOTE:  To my knowledge, Atari never bothered to copyright these
instructions and they are not marked with a copyright symbol.]

[NOTE:  THIS MODIFICATION IS FOR P314 VERSIONS OF THE DEFLECTION BOARD
*ONLY*.  The P327 and P339 versions already have this circuit designed
into the board.  Here is the text from Atari CO-183-02 (1st printing)
which describes a circuit that was sold by Atari to help make the
deflection board more robust.  This circuit is unavailable but very
simple and easy to recreate from the schematics provided herein.]

[NOTE:  Martin Sterni <m-sterni@dsv.su.se> has successfully prototyped
these and is currently selling them WITHOUT ANY COMPONENTS.  He has sent
me a few samples and they are of *superb* quality (nicer than the
original Atari/Wells-Gardner PCBs).  I can vouch for them being produced
properly in every way; I am very impressed!  Contact him if you want to
purchase any.]

NEW INPUT PROTECTION CIRCUIT
FOR WELLS-GARDNER COLOR X-Y DISPLAY
(Supplement to TM-183)

This display contains an additional small printed-circuit board (PCB)
that is not described in the display manual (TM-183).  The PCB is
mounted in "piggy-back" style on top of the Deflection PCB.

The input protection board was added to protect the fuses in the display
from damaging input voltage conditions.  Without this board, the display
fuses might blow in the event of an intermittent or long-term game PCB
failure.  With this board, the screen will momentarily go blank if the
average X- or Y-axis voltage(s) exceed a certain level.  The screen then
automatically recovers for normal game play and earning when the
voltage(s) return to normal.

If this display is used in a Tempest (TM) game, be sure to correctly
adjust the X and Y SIZE and CTR video pots on the Tempest Analog
Vector-Generator (main) PCB [see text immediately above].  The
instructions for these adjustments are printed on the Tempest schematics
- Sheet 2, Side B - 3rd printing or later.  Improper adjustment may
cause the screen to go blank during normal game play.

INPUT PROTECTION CIRCUIT PCB PARTS LIST

Part No.   Description (Reference Designations in parentheses)
---------- -----------------------------------------------------------
24-250107  100 uf Aluminum Elec. Fixed Axial-Lead 25V Capacitor (C1,2)
31-1N914   75V Type-1N914 Switching Diode (CR2-4)
32-1N751A  5.1V 400mW Type-1N751A Zener Diode (CR1)
33-2N3906  PCB Switching and Amplifying Transistor (Q2, 4, 5)
34-2N3904  Type-2N3904 NPN 60V 1-Watt Transistor (Q1, 3)
52-222     22-Gauge Jumper Wire (2 in. required)
110000-223 22K Ohm, +/- 5% 1/4 W Resistor (R1, 8, 11)
110000-273 27K Ohm, +/- 5% 1/4 W Resistor (R5)
110000-393 39K Ohm, +/- 5% 1/4 W Resistor (R4)
110000-682 6.8K Ohm, +/- 5% 1/4 W Resistor (R6, 7)
110001-222 2.2K Ohm, +/- 5% 1/2 W Resistor (R10)
110001-472 4.7K Ohm, +/- 5% 1/2 W Resistor (R9)
110011-122 1.2K Ohm, +/- 1% 1/4 W Metal-Film Resistor (R2, 3)
[110000-102 1K Ohm, +/- 5% 1/4 W Resistor (R')]

INPUT PROTECTION CIRCUIT PCB ASSEMBLY
A038088-01 B

[Figure 1, a scale picture of the top side of the PCB listing numbered
connection points onto the deflection board, has been omitted for
obvious reasons]

SCHEMATIC OF INPUT PROTECTION CIRCUIT PCB [R' added by me as documented
in TM-268]

     Y INPUT             +27V              X INPUT
        :                  :                  :
        :                  *J6                :
        :                  |                  :
        :                  \                  :
        :             CR1  / R1               :
        :           1N751A \ 22K              :
        :            5.1V  /                  :
        :             \    |                  :
        :         +--->|---+                  :
        :         |   \    |                  :
        :   R3   ===       |             R2   :
        :  1.2K   =        |            1.2K  :
        :   1%             |             1%   :
      J3*--/\/\---*--->|---+---|<---*---/\/\--*J1
        |       J4:   CR3     CR2   :J2       |
        |         :  1N914   1N914  :         |
        /         :                 :         \
    R5  \  To R601 1.6K 2%    To R701 1.3K 2% /  R4
    27K /                                     \ 39K
        \   + C2 -                   - C1 +   /
        |   100 uf                   100 uf   |
        |    25 V          J5         25 V    |
        +-----|(-----+-----*-----+-----)|-----+
        |            |     |     |            |
        |            |    ===    |            |
        |     R7     |     =     |     R6     |
        +----/\/\----+           +----/\/\----+
        |    6.8K        +27V         6.8K    |
        |                  :                  |
        |                  *J6                |
        |                  |                  |
        |                  \                  |
    Q4  +-----+  Q3     R' /        Q1  +-----+  Q2
  2N3906|  b  |2N3904   1K \      2N3904|  b  |2N3906
       ---   ---       1/4W/           ---   ---
     c / \ e / \ c         |         c / \ e / \ c
      |   | |   +----------+----------+   | |   |
      |   | |                             | |   |
      |   | +--------------+--------------+ |   |
      |   |                |                |   |
      |  ===              \ / CR4          ===  |
      |   =               --- 1N914         =   |
      |                    |                    |
      +--------------------+--------------------+
      |                Q5  |
      |              2N3906| b
      |                   ---
      |                 c / \ e
      |                  |   +------------------+
      |        +---------+---------+            |
      |        |         |         |            |
      \        \         \         \            |
      / R8     / R11     / R10     / R9         |
      \ 22K    \ 22K     \ 2.2K    \ 4.7K       |
      /        /         / 1/2W    / 1/2W       |
      |        |         |         |            |
    J7*--------+       J9*         *J8          *J5
      :                  :         :           ===
    -27V             To D700   To D600          =
               

COLOR X-Y DISPLAY 92-053
INSTALLATION INSTRUCTIONS
INPUT PROTECTION CIRCUIT PCB

 A038088-01
------------

1.  Remove R600, R605, R700 and R706.
2.  Remove solder from all nine holes indicated in figure 13 [figure not
    included; see text below].
3.  Straighten pins of PCB so that they are perpendicular to the board
    [meaningless to you since you probably don't have the board].
4.  Match and insert the numbered holes in figure 13 with the numbered
    pins in figure 1 [see text below].
5.  Solder.

[Figure 13, an annotated picture of the deflection board PCB from the
original TM-183 manual, has been omitted for obvious reasons.]

[Since you will be making the board from scratch and don't have the
pictures that came with the board, I am providing the following text to
describe the contact points on the deflection board.  The following text
is all mine and *NOT* Atari's but is derived directly from figures 1 and
13 that Atari did provide.]

All descriptions refer to a deflection board oriented component side up
with the board label "P314" at the top (right-side-up) and the 2 large
electrolytic capacitors at the bottom.  This orientation will have the
electrolytics "side by side" and the board will be "taller" than it is
"wide".

J1 is R700's old top pin.
J2 is R700's old bottom pin.
J3 is R600's old top pin.
J4 is R600's old bottom pin.
J5 is the first "empty"/unused hole to the right of C701.
J6 is the first "empty"/unused hole to the right of Q701 and below C701.
J7 is the first "empty"/unused hole to the left of C602 and below D601.
J8 is R606's old left pin.
J9 is R706's old left pin.

SPECIAL NOTE:  According to the Major Havoc manual, this board came in 2
versions.  Later versions had a 1K Ohm, +/-5%, 1/4 W resistor as one of
the "stilts" on the board instead of a plain piece of wire.  If your
board does not have this resistor, here is what you need to do.

   1.  Locate the "stilt" wire connected to resistor R1 (22K ohm) and
       the collectors of transistors Q1 and Q3 (type 2N3904) on the
       Input Protection Circuit PCB (the other end is connected to the
       P314 Deflection PCB).
   2.  Use a wire cutter to cut the wire, located in step 1, half-way
       between the two PCBs.
   3.  Use a soldering iron to solder a 1K Ohm, +/-5%, 1/4 W resistor
       between the two ends of the wire cut in step 2.

I have included this resistor in my ASCII rendering of the schematic
and labeled it R'.

================================================================================

[NOTE:  Play Meter did copyright this article and the magazine is
clearly marked with a copyright symbol.]

Here is an article from the April 15, 1983 issue of Play Meter magazine
(page 191) which is copyrighted material and is included without
permission; forgive me.  It is from a regular feature in the magazine
called "FRANK'S CRANKS" by Frank "The Crank" Seninsky.

HOW TO MAKE A 'TEMPEST' MONITOR TROUBLE-FREE.

Atari's Tempest, when it is working, is not a bad game.  It's just a
shame that the monitors only last a few weeks (sometimes only days)
between service calls.  Most of the time, the monitor sits neglected on
a techroom shelf.

Atari has developed a monitor protection board [included earlier in this
text] to protect the monitor's components (2N3716 and 2N3792 "X" OUTput
transistors, two each located on chassis frame) if and when there is a
RAM lock-up on the Tempest CPU board.  I want to clarify that the
Wells-Gardner monitor is not at fault.  Also note that on the later
Atari games, the protection circuit has been incorporated into the board
circuitry.  [These statements seem to imply that this "fix" is
compatible with the Atari upgraded P314s as well as P327s and P339s and
will provide additional protection; if fact, I have seen it on a P327
before.  It is sufficiently ambiguous that the exact opposite can be
inferred.  Judging from the areas of the board it alters, I would say it
is incompatible (duplicates) the other fixes in this section.]

It's common knowledge that you can purchase a broken Tempest game cheap.
With about 20 minutes of your time and a couple of dollars in parts, it
is possible to add just six common components to the monitor deflection
board and have a Tempest that will stay on location and work [Yeah,
right]!

The parts required are:
   two-1N914 diodes
   two-1N4737 diodes
   two-1K OHM 1/4 W resistors

FIRST HALF
Take the anode ends (the ends opposite from the marked rings) of a
1N914 and a 1N4737, and solder them to one end of a 1K ohm resistor so
that it looks like this:

                               ANODE +------+-+ CATHODE
                            +--------+1N4737| +--------+ GROUND
CATHODE +-+------+ ANODE   /         +------+-+        |
--------+ | 1N914+--------+                           ===  C700
R700    +-+------+         \         +--------+        |
                            +--------+ 1K ohm +--------+ -27 VOLTS
                                     +--------+

Locate C700 in the top left of the monitor deflection board.  (See
Figure 13 on page 20 of Atari TM-183 Wells-Gardner Quadrascan service
manual; second printing) and solder the cathode of the 1N4737 to the
ground side of C700 (right side in Figure 13).  Solder the end of the 1K
OHM resistor to the -27 volt side (left side) of C700.  Solder the one
remaining wire (the cathode of 1N914) to the "X" INput side of R700 (top
end of R700).  You are now halfway finished.

HALF TIME
Take a five-minute break; you deserve it.

SECOND HALF
Take the remaining 1N914 and 1N7437, and solder the cathode ends of each
diode together with one end of the 1K OHM resistor so it looks like
this:

             ANODE +------+-+ CATHODE
GROUND    +--------+1N4737| +--------+
          |        +------+-+         \ CATHODE +-+------+   ANODE
C701     ===                           +--------+ | 1N914+--------
          |        +--------+         /         +-+------+    R700
+27 VOLTS +--------+ 1K ohm +--------+
                   +--------+

Locate C701 (top middle in Figure 13) and solder the anode of 1N4737 to
the ground side of C701 (right side).  Solder the end of the 1K OHM
resistor to the +27 volt side of C701 (left side).  Go back to the same
"X" INput side of R700 and solder the remaining wire (the anode of the
1N914) to this connection.  Make sure that you have a good solder
connection at the "X" INput of R700 as you now have a three-wire joint.

FINAL TWO-MINUTE WARNING
Make sure that none of the wires of this modification can come into
contact with the other board components [easy to do; there is lots of
bare PCB in this area; you may want to tape/glue the leads down],
especially the brown ground wire located to the right of R700.  If the
modification hits this brown wire, you can consider it a fumble and you
just blew your lead and the game.

================================================================================

Lastly, I will list 2 hacks that I have seen made to deflection boards
in an attempt to get them to work for longer periods in the field.  I
have seen them on both the P314 and P327 designs.  The first one makes
some sense but the second one is downright scary!

Cut the trace just above pin 4 of connector P101 isolating the 3 topmost
connections (purple wire, R713, and pin 7 of P700) from the rest of the
cluster.  Jumper the 3 isolated connections to pin 7 of P100.  This
makes those 3 connections run at -33.3V instead of the usual -27.7V.

Cut the trace just to the left of pin 3 of P101 isolating the 5
rightmost connections (F700, R808, pin 5 of P701, C104, and R712) from
the rest of the cluster.  Jumper the 5 isolated connections to pin 1 of
P100.  This makes those 5 connections run at 33.8V instead of the usual
27.8V.

I am not sure what is gained by biasing these portions of the circuit by
larger magnitude voltages but will look into it later.

When I saw this next hack, I couldn't believe my eyes; especially after
I plugged it in and IT WORKED!  The hack described above was implemented
but with the following additions...

Evidently this operator got so tired of fixing the low voltage power
supply regulator circuitry that he ELIMINATED IT FROM THE CIRCUIT!  What
he did was remove virtually that entire section (R100-103, D104-105, and
P100) and instead formed the voltages required by dropping the
unregulated +/-33 voltages across resistors!  He connected a 10 Watt, 25
Ohm (+/- 10%) resistor between pins 3 and 7 of P100.  An identical
resistor was connected between pins 1 and 4 of P100.  I'm not sure what
kind of solder he used but it is takes a good minute for a 30 Watt
soldering iron to even begin to melt a small portion of it.

This change will give you a very noisy approximation of the original
voltages that should be good enough to run the monitor.  Needless to
say, the ceramic resistors get unbelievably hot and the screen is a
little jumpy when drastic changes in drawing (current pull) occur (such
as between waves and during the demo) but other than that the results
are quite tolerable.  If run for extended periods, this setup is
virtually guaranteed to blow some fuses on the deflection board.

Since there is no longer a Q101 to worry about, it won't cause you any
problems and since P100 no longer exists (either it or the connector
that goes to it should be removed to avoid somebody plugging it in and
adding the transistors to the now foreign circuit), there won't be any
problems with Q102 and Q103 either (they are no longer required in the
circuit and the connector that went on the now missing P100 just hangs
in the air).  If you are going to be placing one of these monitors out
in the field or it is going to get frequent, extended duration use, this
hack *might* be worth trying (assuming the degradation of picture
quality is acceptable to the viewers) but I would think it would greatly
stress the rest of the circuitry as well as the yoke coils and would
limit the lifetime of the unit in other, less familiar ways.  The PCB I
saw this on had extensive burns on the amplification portions of the
circuit which I almost never have to repair so BEWARE; this hack may
have been the cause not the solution!

 


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