2 Sound Q's: MK and TMNT

modessitt

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Went and looked at some games yesterday, and fixed them all but two with sound issues:

Mortal Kombat - Everything seems to work fine except for some of the sounds. None of the voices work ("Fight!", "Finish him!", "Hiya!") and the smack noises also don't work. The voices sound garbled and unrecognizable, and the smack noises just give a faint "pfft". However, the tunes work just fine. Sound diagnostics don't tell me anything specific. I just advance through the five sounds and the tunes play fine while the smack and the Hiya do not.

I'm thinking this may be a bad sound ROM, or possible a cap issue? If it's a ROM, anyone know which specific one(s) I should replace to see?

Another thing is that I can't enter Test through the switch inside the coin door, so I had to do so via dip switch. When it was on Coin Play, hitting a coin switch caused the game to jump to a COIN SETTINGS SET BY CMOS screen, then back to the title screen that would let you play. Once on Free Play, that stopped happening.

Any advice is appreciated...

TMNT - When first turned on, this game works fine - sounds and all. After being on for a while (maybe 20 minutes), the sound starts getting static-y. Turn off and right back on and it stays static-y, so it appears to be heat-related. Should I suspects caps, ROMs, or maybe the amp? Any advice is is appreciated...
 
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MK issues: hold down your test button in the coin door if it's a momentary switch (unfortunately you'll have to keep it pressed down for the duration).

as for the sound board, i'd put my $ on a bad or dirty rom. clean the legs first and resocket if that doesn't work reburn (there's only a couple).
 
TMNT sounds like caps to me but if it is the amp then you could spray it with some chip cooler or compressed air to see if the sound goes back to normal.
 
TMNT - When first turned on, this game works fine - sounds and all. After being on for a while (maybe 20 minutes), the sound starts getting static-y. Turn off and right back on and it stays static-y, so it appears to be heat-related. Should I suspects caps, ROMs, or maybe the amp? Any advice is is appreciated...

Common issue. If is the same issue that I, and countless others, have... then there isn't a real fix for it (yet).


Mine started off just getting static sounds every once and a while... then eventually ended up like you see in the video. Same with a friend's TMNT boards. Sucks because it's a great game... but the audio issues are just a nightmare with this thing.
 
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The Yamaha sound chip plays the music... many sound effects are done by the small flat, square, surface mount OKI chip and the 2 ROMs connected to it have the sound samples in them.

Check for bad ROMs, bad sockets, bad traces, OKI chip, and op-amps/caps associated with that part of the audio circuit.
 
The Yamaha sound chip plays the music... many sound effects are done by the small flat, square, surface mount OKI chip and the 2 ROMs connected to it have the sound samples in them.

Check for bad ROMs, bad sockets, bad traces, OKI chip, and op-amps/caps associated with that part of the audio circuit.

Exact sentiments. Was gonna say those sounds are controlled by the Oki chip lol
 
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