[sdiy] CS-50

[Gavin & Delia]

I know there are some Yamaha CS pros out there, in fact I'm a bit of one
myself but this issue has me stumped.  Audio-wise I get real low or no
output on all 4 voices.  Originally the keyboard wasn't affecting the sound
either but I discovered the culprit was a blown 4016 on the S/H board.  I've
traced both signal and CV all the way to the VCA section of the M (voice)
boards and it all looks good, but on at least one if not more of those SIP
iG001501 (?) chips there's no or low output.  Looks like blown VCA chips,
but seems strange that they would all go like that, so maybe something later
on pulling down the output?  
Just checking in to see if anyone's had a similar issue before I spend
another big block of time pulling my hair out tracing out the signal path!\
thanks
G.