Donkey Kong 4 Board PCB Sound Issues

Phetishboy

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I finally got the sound working on my DK cabaret with the installation of a new 50K volume pot. Now that I have sound, I can tell some of the actual sounds are off. The lower bassy sounds seem fine, but the higher pitched sounds like 'jump' and 'die' sound horribly distorted and extremely tinny. Where should I be looking?
 
I finally got the sound working on my DK cabaret with the installation of a new 50K volume pot. Now that I have sound, I can tell some of the actual sounds are off. The lower bassy sounds seem fine, but the higher pitched sounds like 'jump' and 'die' sound horribly distorted and extremely tinny. Where should I be looking?

I had this exact same problem. I recapped the audio board and it didn't fix it until I replaced the fusable resistor (R383 on the sound board).


IMG_20110929_213351.jpg


Here are my two threads, the second one has all the details:
http://forums.arcade-museum.com/showthread.php?t=193232
http://forums.arcade-museum.com/showthread.php?p=1797330

Since I couldn't find a fusable resistor I replaced it with a standard 39Ω resistor and I put a inline fuse holder on the wire (BK) coming in on connector JC put a .5A fuse in it.


Here is what mine sounded like before I replaced R383



After I replaced R383.

 
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Before you go all bananas doing that...do you have another audio amp you can test in the cab first? Just to make sure it's the amp and not the pcb?
 
Great info Tighe. Hey Brad, I do not. I do have 2 - 13 inch Sanyos here, but they seem to have different audio amps. The volume pot is incorporated into the older one, but on a remote board on the newer one. I am not sure if they are compatible, but I can check this weekend.
 
If you have some spare PC speakers you can use them to test the audio. That is what I did when I was having problems. I used a CD rom audio cable and a audio patch cable to make an adapter:

 
If you have some spare PC speakers you can use them to test the audio. That is what I did when I was having problems. I used a CD rom audio cable and a audio patch cable to make an adapter:

Yeah, I doubt I'll be doing that. I will be pulling the board, checking the sound board over, cleaning and re-seating chips. Then I will take a look at that resistor.
 
Ok, I didn't have time to do any soldering this morning, but in addition to buying 3 of the fusable resistors, I also bought a complete replacement sound amp from Rip. I installed that instead and everything sounds normal again. The only issue I am having is that the heat sinks on the repro sound amp are like 1/4" taller than the ones on the original. They may fit fine on the 19 inch Sanyos, but on these tight 13 inch Sanyos the heat sinks push up against the yoke. Will that be an issue? I was able to get the bracket mounted, but everything is pushed out at an angle due to the conflict between the yoke and the sound amp.
 
Cool thanks for sharing. I hadn't thought about the height causing issues.

Fixing the original is easy enough anyways.

More I am curious if it still has that Nintendo hum.
 
Repaired 3 more sound boards by replacing the fusable resistor at R383. Glad I heard about this fix. Still have one that is completely dead after new caps, new transistors and the new resistor, but at least I fixed 3 of the 4.
 
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