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CPS-1 Sound Issue

GeorgeSpinner

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I have a CPS-1 with bad sound.

I say "bad sound" instead of "no sound", because it does play some sounds nice and clear.

It does not play any music.

The A PCB is the 89626A-4 12 mhz DASH model.

The B PCB is a Daimakaimura (Japanese Ghouls n Ghosts) reproduction. 91634B-2.

I did not create the roms.

In the test menu, it will play some of the sound effects, but none of the music.

No sound is made when inserting a credit.

When the opening scene plays out (after pressing start), only 2 sounds are played (no music), when the 2 characters are cut down by the demon.

When the game begins, 1 sound is made. That sound kind of echoes and then there is nothing but silence until the power is cycled.

I have created a video that demonstrates the issues I am describing: youtu.be/f1tHsWFhHc0

Does anyone know what may cause this issue?

My searches have revealed it could be the z80 but I do not want to just start replacing parts (although that may be required).

The game was working perfectly for about 35-40 minutes (level 5 for the 2nd time) and then a loud noise was emitted. After that, the sound cut out and it has been in the state described above.

I removed all the roms and cleaned all the sockets today. No change.

I originally posted this in the "Other Capcom..." section. Somehow, my brain was not willing to see the CPS1 section. I apologize for the bad first impression.

Thanks for your time.
 
If only samples work I'd have a look in the last stages of audio processing (pre-amp, DAC = YM3012 IIRC, etc.).
It's easy to troubleshoot if you have an audio probe.
 
Last edited by a moderator:
The new (to me) A board seems to have resolved my issue.

Although the exact cause was not identified, the solution at least reveals there is probably nothing wrong with the B board.

Thanks for the help.
 
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