[sdiy] ARP 3604P Keyboard

[klosmon]

I'm currently trying to repair a 2600 with a 3604 keyboard -- this is 
the first time I've dealt with one of these (always had the later keyboard).
There was apparently a catastrophic power event;  bypass caps, two 
transistors & the opamp were dead.  Replaced all those, all other 
transistors tested good.  Everything is now working, except that the CV 
output drops after releasing the key.
All three capacitors in the CV memory circuit (C6, 7 & 8) all test good, 
but I replaced them anyway -- no help.
Also triple-checked the circuit board traces (since these solder-trace 
boards can suffer from rework), and it's all correct.

Can anyone point me towards a solution?  Or does this type of keyboard 
behave that way normally?

Thanks.

~GMM