Minimoog D with early oscillator board

Hi!

I have a Minfooger D with early oscillator board.
Osc 3 not oscillating, no sawtooth on neg side of C8 , just sitting at 0v.

I have schematic + theory of operation writeup, a dmm and a scope, where should I start? Any common component failures?

Osc 1 and 2 are working, so should be a good comparison for voltages and waveforms.

Thanks in advance.