I have a constant voltage of just under +5 on the ST side of C35, and -5 on the side toward IC14.
The synth won't go into manual mode, tho the switch does light on occasion. Any attempt to adjust a pot or switch will change settings in a seemingly random manner, causing a new patch to come up, or more often, noise.The program and bank lights do not always come with a patch, and sometimes when they do light, there is no sound.
Apologies for the side track with IC17. I just noticed those voltage while poking around, and was puzzled. However, as the synth goes thru it's random routine, the Write button does sometimes light or even blink.
And as always, I appreciate the overview you are so kind to include. Will need to reread in the morning.