Donkey Kong Sound Problem - Death Sound Taking Over - Can't find 4 Board Schematics

[TokensArcade]

Donkey Kong Sound Problem - Death Sound Taking Over - Can't find 4 Board Schematics

Hello KLOV:

My Donkey Kong Cocktail table with a 4-Board Stack recently developed an annoying sound problem.

Basically when the game starts, everything seems normal but then the music that plays before the stage sounds "off" and a bit crunchy. The game sounds seem normal except when the player dies, there's no death music. Once I beat the first stage, then it seems the entire sound logic comes apart at the seams. The death sound effect now seems to play instead of every other sound effect and music cue. The gameplay and graphics seem fine, it's just the sound is all screwy.

Here's Part 1 of a video that shows the problem. Things get really weird after I reach Pauline in the first stage.

https://www.youtube.com/watch?v=Pt1eG9ca91M

I tried capping my monitor's sound amp as well as re-seating the roms and other IC's on the sound board, but no effect. It should also be mentioned that while what I've described previously is what most commonly happens, sometimes other audio anomalies come and go too. I have a feeling this is an issue with either the TTL components or caps on the board. It seems as if there's like a stuck gate open that is triggering the sound effects at the wrong times. The problem is that I can't find any schematics for the 4 board version of Donkey Kong so I'm not sure where to start. All the documentation I can find just specifies what roms the sound effects are stored on, not the logic as to how to trigger them. I found a thread somewhere that detailed how to jump wires to trigger sound for the 2-Board version, but not the 4-Board version.

Can anyone link me to a schematic of the Sound board for the 4 Board Donkey Kong Stack? I have TGK3-007 SOU

It should also be mentioned that this is actually not the first time this has happened with this machine. It happened just short of a year ago and all I did was take the Sound board out to see if there was anything visibly wrong, then reassembled everything and it went away and hadn't re-appeared until a few days ago. Now this problem seems here to stay.

Please respond with any help or advice you may have and have a good day.

 

[pinge80]

Sadly Im of no help but I am in the same boat. I have a 4-stack looping the deathsound over and over, It starts already on level one and as you say it seems to play instead of other sounds.

I took the easy way out and got another working board...
I will follow this thread and hope you solve the problem and share your wisdom

 

[hailrazer]

Member Jamburglar has copies of all the DK board revision schematics.

 

[TokensArcade]

Member Jamburglar has copies of all the DK board revision schematics.

I just sent him a message.

If I can just figure out the discrete logic of how triggering the sound effects works, I feel I might be able to trace a potential stuck gate with my logic probe. But of course, I need to know where to look first.

 

[TokensArcade]

Well well well, just as I was about to cave in and pay someone online to fix it. The problem seems to have disappeared. I took another look at the board stack and I reseated a ROM on the CPU board which had a dust bunny under it (not in the pins though), reseated the MPU AGAIN, wiggled the capacitors on the sound board do check for any with corroded or loose legs, and turned the VR1 "Sound balance pot" a bit to the left (out of sheer curiosity and desperation, frankly) and low and behold, the death sound is back and playing correctly!

I let it sit for a while, played multiple games, turned off and on a few times and it seems the problem has gone away!

I have no idea if anything I did was what actually fixed it or if it's just some weird freak accident thing. I don't suppose anyone here would be able to make sense of what happened to it. Could my VR1 pot be going bad? Cranked too high?

I'm letting it sit for a couple days now, I'm going to try it again later to see if it's still gone. Will post again with results.

 

[TokensArcade]

Weeeeeeell shit, it's back again. :/

Tried all the stuff I did last time, but the death sound is missing again.

Any further suggestions?

 

[Ace20]

For anyone looking for a solution to this problem and comes across this thread. The issue is the smaller of the two cables that connect the sound board to the cpu board, it's the one that looks like an old pc floppy disk drive power cable.

It uses badly designed crimp pins that only connect on three sides that bent out and eventually lose contact. I made a new cable with more modern crimps / housings and that fixed the issue.

 

[TokensArcade]

For anyone looking for a solution to this problem and comes across this thread. The issue is the smaller of the two cables that connect the sound board to the cpu board, it's the one that looks like an old pc floppy disk drive power cable.

It uses badly designed crimp pins that only connect on three sides that bent out and eventually lose contact. I made a new cable with more modern crimps / housings and that fixed the issue.

That may have been part of it, but I actually ended up paying a guy on Ebay to repair it and he said that the main issue was that the DAC was failing. That chip has now been replaced as well as some of the diodes I believe. My DK has been working like a champ for over 4 years since the repair!