Vintage Synth Repair

Hi folks,

I know I should really be looking to get a brand new, modern PSU but I am working on a fault on a Moog 910 power supply. Would like to get it working just so I can check out all the other bits... and then look to getting a better power supply later on.

Anyway, my -10 volts is sitting at around -15.8v. R15 (33ohm) looked a little burned but it still read 34ohms. I changed it anyway. Also changed C8 and C9 and swapped the two DTG100's around (to prove a point) No difference.

+12volts and -6volts set perfectly... I am baffled, how is the -10volts derived...? There is just the 33ohms between it and the -16volts which is the main, fused, half wave rectified rail..!?

Can anyone shed any light or even come across this fault before please?

Cheers,
TOM