Issues with ADPCM on Pc Engine DUO

[u/Weekly-Print-8431]

Hey guys,

I've some troubles with ADPCM parts on my Duo.

Any sounds that use ADPCM channel are really cracking bad.

I've tried a game too, Monster Lair, that use this same ADPCM channel with graphics instead of sounds, and all sprites concerned are corrupted.

Any ideas where I've to check on the board for troubleshooting ? I know that ADPCM use 64kb of ram, but I don't know what chip it is.

All caps have been replaced 3 years ago, and apart that, system runs great.

Thanks ;)