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djsheep

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I was wondering if anyone can help me with the issue that my TMNT PCB is having.

When the game boots the sound seems fine (although loud) however when playing the game, while samples are played they're distorted, fuzzy and scratchy *AND* at the same time the samples play the music simultaneously becomes scratchy and fuzzy, the music will sometimes return to to normal if no other sample is triggered.

As the game goes on through the levels this gets worse and worse until you reach the final level and it's one big scratchy loud distorted mess (samples and music).

The lowest end setting of the volume pot it is quite loud, it almost sounds like when you run a Stereo signal through Mono.

I've tried and tested it extensively on multiple cabs, the supergun, and adjusted the voltage accordingly with no luck.

I've read a lot of similar reports on various forums and know this isn't an isolated incident, but there's many fixes that work for some and not for others and I'm hopeful someone here has better insight on a fix. Thanks in advance.
 
Are you saying that when the volume pot is at 0% there's still sound? If so that leads me to think it's a faulty pot.
 
Are you saying that when the volume pot is at 0% there's still sound? If so that leads me to think it's a faulty pot.
Not at zero. At say 1 or 2 on the dial of 10.
 
Had this on my TMHT as well, from memory it was caps and maybe 1 new sound rom but not sure anymore as it was a long time ago.

It is pretty common though so you should have not a lot of issues finding the cause.
Perhaps it is on the repair log website from @caius as well?
 
@PascalP -- There's a heap of forum posts and repair logs with varied fixes and levels of success. I was just hoping someone had narrowed it down to a particular thing or two and not a rehaul of so many different parts... lots of conflicting information out there regarding this issue.
 
Start with the tantalum caps in the sound section (link).

Repair log was written by @yavuzg

The ultimate solution for my board's sound problem was to replace the 4.7uF tantalum capacitors (C6 and C74).
That is where I got to. There are still sound problems on my board, but this sorted out the intermittent sound issue.
 
Mine still sounds mostly good, but I've noticed the metal sounds (like cutting a parking meter or jump attacking a foot helicopter) sounds a little scratchy.
 
Will report back after I change the caps and let ya'll know...
 
I have these symptoms on my TMNT2 (i've tried few m27c160 and didn't have any success with :S ).
 
Will report back after I change the caps and let ya'll know...
Hello Guys,

Basically, most of our lovely boards needs to be recapped, like any other computers or console.

On my TMNT board, i had the same problem, glitchy and scratchy music and sound. The capacitors seems ok externally, but can't count. One i replaced them with top Panasonic/Nichicon ones, and turn on back the game, guess what ?

ALL PRETTY MUSIC & SOUND FX !!! no more Glitchy and Scratchy play nuts :D :D !
 
I got a TMNT board that had the exact issues as this video:
At 5 volts, the issue would show up around 20/30 minutes. If I lowered the voltage to 4.5 volts, it would take much longer for the scratchiness to start, and even longer for the sound to cut out completely. To solve the problem, the three tantalums next to the sound amp heatsink were replaced (C6, C74, C73) and *poof*, my sound effects and music are perfect. Didn't see a mention of tantalums in this thread, hope it helps someone. Good luck!
tmnt-arcade-tantalums.jpeg
 
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@Frank_fjs fixed mine, I think he recapped the whole thing.

However now I have a problem where the theme song at the start of the game plays one part wrong... such a troublesome PCB it seems!
 
@Frank_fjs did you do a full recap? All of them? Or did you target the two mentioned in the other thread?

If you did them all, did you do the two first to see if it fixed it and then continued, or not?
 
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