Yamaha CS80

Hello everyone.

I�m newbie here and cs80 and cs60 owner from Finland. Second cs80 
should come from London next week. I wonder if i find here someone who 
can solve my problems with cs80. The problem is that in ch-2 voice #4 
doesn�t sound at all? In ch-1 it�s normal but ch-2 it�s like muted. 
Also voice #6 sounds very loud, like only aftertouch could hear very 
loud but normal sound is quiet? I have repaired all the downstears ic-
chips and add ceramic-capasitors under KAS-board for every chips like 
oldcrow adviced. So total of over 50 new chips! That�s why i think the 
main problem is somewhere else. I have think that maybe M-board-5 and 
6? Please help me if someone understand my problem cause can�t find 
any help from here Finland! Thank you for your excellend sites.
ESKO