I just got a Matrix 1000, seems great, but I have voice issues in some patches, occasionally I'll come across a patch where two voices are a lot quieter or seem thinner or don't play. Other than that it seems to be working fine about 95% of the time.

There was one patch where lots seemed kind of messed up, maybe that was the patch though (984) doesn't play up high in the register some don't play some seem thin.

Is this usually fixed by replacing the CEM3396 chips is there a diagnostic to figure out which need to be replaced, or is it just advisable to replace them all if you're having trouble Or is this something completely different

Thanks in advance!
-Dave