IC3 is the LFO, that's the one we're interested in. Many of the pins are tied together, so you should see the same voltages on pins 13, 4, & 8.
Pins 9, 10 & 12 will be the same.
Pins 5 & 7 will be the same.
Pins 3 & 14 will be the same.
Pins 2 & 15 don't matter.
Pins 1 & 16 should both be around 1.2V to 1.3V and not vary much, if at all.
Pin 6 is power, Pin 11 is ground.
With the LFO stalled, all of the voltages on yours should be constant.
Have you verified R28-R30? If any of those are off, the LFO can stall.
If the LM13700s are socketed, you can try swapping IC3 for one of the other ones.
Where are the photos? I want to see if you got the mods right.