I have applied all the logic I know, and I have to accept its answer. I have five dead (or dying) 2044s and five dead (or stuck) 2056s. Luckily the good remaining VCF and EG SSMs work in all the V0-V5 channels, so at least the underlying circuits are good, if needing calibration. But what is the chance of so many dud ICs! My luck, I guess.
Shocked by the cost of the replacements, especially the EG. I have managed to source both for cheaper in China through Ali Express.
Does anyone have any experience of far eastern chips? Anything I should beware of?
I have learned more in the past 12 hours about analog synths that I have in a lifetime. Thank you again for your kind support - This Polysix (del volante) will live again.
Moon