Donkey Kong (Nintendo) PCB repairs
Problem: No pounding sound from Kong
Missing only Kong sounds when he
jumps on and breaks the girders in the introduction and no sound when
he pounds on the girders.
Tools: soldering iron
First, I cleaned and re-seated all the eproms and the 8039, no change.
I replaced C24 elec. cap, as it was corroded leg was falling off,
still no Kong pounding sound. Then reheated the solder on all the
caps and transistors around the area of C22 and the ones around two
sound eproms. Viola! It worked. Now, if I could only figure out
which cap did the trick. It's nice to hear Kong again.
Solution: reflow the solder on the caps in the sound circuit.
Problem: loud hum sound at all volume levels
The Sanyo monitor has a small audio amplifier board on it, I
swapped the board with another one and the hum disappeared. Looking closer
at the board I bent back the electrolytic capacitor at C387 and the leg came off
in my hand. I replaced the cap and reflowed the solder on the other electrolytic
capacitors and re-installed the board. When I powered up the game,
the hum was gone.
Solution: replace bad electrolytic capacitor and reflow the solder joints
on the monitor's sound amplifier board
Problem: missing grin sound during into
I don't know what else to call this sound, but after Kong
climbs the girders and stomps on them to break them all, he grins and you
hear a kind of heee, heee, heee sound. Anyway, it's a digital sound. To
make a long story short, I finally changed the sound EPROM at 3F and that
fixed the problem, Kong is now grinning away and you can hear him again.
Solution: replace bad EPROM at 3F on the CPU board.
Problem: Missing sprites
There were NO moving sprites on this board at all. The ladder
at the beginning would move up and when Kong pounded on the girders they would
break, but Kong, Mario, the barrels and everything else that moved was missing
Solution: Replaced bad MC10125 at 1H on the Video board.
Problem: No digital sounds
Solution: Broken 10K pot at VR1
Problem: TKG3 board set - Board will not sync
I replaced the pots and no change. All the LS161/163s were pulsing.
Looking at the schematics, there is a 74LS02 connected to the VBLK/CMPBLK outputs.
I noticed that if I shorted pins 2 and 3 on the LS02, the picture would semi-straighten
up. Replacing the chip fixed the board.
Solution: 74LS02 at 1C on the CLK board at 1C
Problem: Missing all motion sprites
All sprites were missing, the I finally traced from that data lines
back to see where a chip had died. When I got to the LS237 at 6J, it was dead. Probing the clock line, I found
there was no clock on pin 1. The clock comes from pin 10 of the LS139 at 5F. Pins 13 and 14 had input on that
chip, but there was no output on pin 10. Replacing the chip fixed the board.
Solution: Bad LS139 at 5F on the video board.
Problem: Very low sound output for digital sound.
I first put in a new 8035 and both sound roms, 3F & 3H. No change.
Looking at the output of the 8035 with my logic probe, I could see that there was data. Next, I checked the
inputs of the DAC08 when music is playing during game play. Data here too. Looking at the output of the DAC08
at pin 4 showed that is seemed to be working fine also. Next on to the MB8314 (LM324) at 7K. The input on pin
13 from the DAC08 was fine, but the output on 14 seemed to remain low with my probe. Replacing the LM324 fixed
the sound problem.
Solution: Replaced bad LM324 at 7K on the CPU board.
Problem: Sparklies on Kong's lower lip when he grins and on the barrels in the top-left section
of the first level.
Solution: Bad 73LS163 at 3E on the video board
Problem: Background tone always present, walk sound off.
Sounds like the walk sound never completely cuts off.
Solution: replace transistor Q6 on the CPU board, a 2SC 1815
Problem: Whirring sound all the time.
Sounds like the jump sound never completely cuts off.
Solution: replace transistor Q4 on the CPU board, a 2SC 1815
Problem: Picture takes several seconds to sync, and
characters are broken
up in slivers, sections are up or down from where they should be.
Normally this is a 74LS163 at either 3E of 4E on the video board, but
replacing both of these chips did not change the problem. I noticed if I press on the section of the board with
these chips, the picture would somewhat fix itself. Running my fingers on the bottom of the MC10105 at 1F on the
video board would really mess up the characters even more than they were. Replacing the chip fixed both the slow
sync up and the characters.
Solution: Replaced faulty MC10105 at 1F on the video board.
Problem: Sprites appear to walk behind invisible vertical slats
I used the bugtrap for this one, I suspected the LS157's on the bottom of the video board, and
one at 7S shows a non-matching output. Replacing the faulty chip did not fix the problem. Next I looked at the
LS283 ADDR chips and jumpered a good chip on the one at 8R and the screen cleared up. Replacing the LS283 at 8R
on the video board fixed the baord.
Solution: Bad ADDR 74LS283 at 8R
Problem: Flat walk sound - TKG4-11-CPU
Ok, I'm working on a Donkey Kong board for a fellow KLOV'r and he points out the walk sound is
'flat', no pitch change at all. I can verify this is by shorting the base and collector (Pins 2 and 3) of Q6 to
turn on the raw sound. The sound was a steady pitch, no oscillation at all...
I told the board owner, it was normal on all TKG4-11-CPU's to have this same flat walk sound. After a bit of a
protest and pointing to folks pointing to my repair logs, I agreed to look it over again and see if it was
indeed just something that TKG4-11-CPU owners had to live with.
Anyway, I spent yesterday afternoon testing resisters, replacing the two chips (4049 and 556 timer), and all
caps in that circuit, including the big green guys. Surely after replacing or testing every component in that
circuit, I had to have nail it, but NO CHANGE! Still that dang flat walk sound.
So.... just for fun I start following traces and matching them to the schematics I have, TRS, TKG4-13 and 14.
It turns out that the little circuit with the two inverters from the 4049 are backwards on the board. Hmm. R48
runs to pin 12 of the 4049, and C30 connects to pin 9, which is backwards from all the schematics, but
reversing them seemed has no effect. Back to square 1....
This morning, remembering what I had told the board owner at first (All TKG4-11's sound like this) I start
gathering up my different version of CPU boards and checking the sound output for walk...
Well, what do you know.. all 6 of the TKG4-11-CPU's have a flat walk sound, as I previously thought, but all
the other CPU's have the normal 'warble'.
It has just got to be those two swapped pins in the 4049 circuit. Otherwise why would they change it in future
revisions and why was it different on the 4 board sets? So, I cut two traces and jumpered the circuit to match
the schematics and.... lo and behold... warble!!! I must have missed something by not cutting traces the first
Solution: So, the fix for the TKG4-11-CPU flat walk sound is...
Cut trace from pin 12 of the 4049 at 8L to the 4.7K resistor R48 (cut the trace on top of the board between R47
and R48) and jumper the loose end of R48 to pin 9 on the 4049 at 8L. Then cut the trace between pin 9 on the 4049
at 8L and the - (negative) side of C30 (on the bottom of the board), then jumper the - side of C30 to pin 12 of
the 4049. Done! I did both the jumpers on the bottom of the board.
Problem: Missing Sprites
Tools: Logic Probe and BugTrap 1674
Pin 13 of the 82s09 ram was stuck high. Traced it back to a bad LS161 at 5K. Verified LS161 was bad with the BugTrap 1674 chip comparator. Replacing that chip restored the sprites.
Solution: Bad LS161 at 5K
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