Circuitbenders Forum
Circuitbenders Forum => Circuitbending discussion => Synths & Samplers => Topic started by: mmontag on October 23, 2021, 12:37:18 PM
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Hello all,
I have a PSS-480 that has a weird "intermittent percussion" problem. Triggering drums with keyboard (percussion keys) might work for a few seconds, then triggers start getting ignored. Same behavior playing built in rhythm patterns or the demo song; drums go silent for a stretch and then come back.
The PCM drum sample themselves don't get clipped off; it seems to be only the *trigger* that gets ignored sporadically.
It seems to be random, I haven't discovered a cyclic pattern or anything.
Does anyone have any clue what could possibly cause this behavior and if it's worth trying to fix? Hard to imagine old capacitors could cause it.
- I downloaded the service manual PDF, available online at many fine websites.
- This keyboard uses YM3419 (RYP7) for percussion sounds.
- When started in test mode, it passes all ROM/RAM tests. But the drop-out problem remains.
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For a future Google searcher:
It turns out the problem was cold solder joints on the YM3419B chip. I was about half-way through recapping the whole thing, and that didn't make any difference.
I reflowed solder around the whole chip and that was enough to fix it for good.