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Happy
Grand Master
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Hello my friends, I just got my S24 board from yahoo japan, and got the multi working but I have no music, even if I get sound effects.

I think there's something wrong with the board, anyone has an idea where to look ?

Thanks
 
Hi guys, I've been doing some researches until today with @Apocalypse who gave me some good starting points to learn how to fix this board.

The board has 2 sound chips YM2161 and YM3012 which work in conjunction to produce music + mix of serial digital and analog voices.

I have done some audio listening with a speaker on pin 21 on the YM2161 chip and I can hear music with scratch sounds.

The same music goes until the YM3012 then nothing happens in this chip.

Then I started probing the YM2161 and YM3012 with a logic probe.

YM2161 : gave me IRQ and ICL stuck high on the YM2161, I tried to find where they are connected, IRQ is connected to Sega chip 315-5295 > (IC7) and ICL goes to Sega chip 315-5296 (IC67). Stuck high too with no short in between. CT1 and CT2 are stuck low.


YM3012 : ICL is also stuck high like the other, and all outputs are stuck high except the ground which is naturally stuck low.



I'm starting to think possibility is every sound chip could be failing, but also the 315-5296 and 315-5295 or maybe something else out of my understanding.


Any help is welcome, not lazy to learn, gain some skills and share the fix.

9tB1toH.jpg
 

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