I will check your suggestions.
In my case, each individual voice fails, when tested one at a time.
When "All" is select, they also all fail.
I did find 2 bad CEM3374's that were not outputting the triangle waves on the 4 output pins.
These were the first chips I replaced.
I have rebuilt the power supply. As I have a large collection of the civilian/military style caps, I replaced every cap on the power supply with the same style that was installed.
I have less than 10 mv of ripple on every output voltage pin.
(This should be more than acceptable, given the age of the power supply design, 30KHz switching supply).
I recapped the voice board - just the 2.2uF caps & the 2 15iF caps by the LM311 I.C.
I have ordered a CMOS & TTL tester, so I can check the I.C.'s one at a time before just "Blindly" replacing.
I know from experience that the CD4054 & CD4051 tend to go bad, but I will verify with tester before replacing.
Thank you for your post. It will be very helpful.
