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Help with modded Dynaco ST-70?

With all 4 E88CC tubes in I'm getting a plate voltage of around 45V after it settles and approximately:
G1: ~-0.6
G2: ~15V
C1: ~-1.1
C2: ~15V

With preamp tubes pulled from one channel so I don't drop the voltage quite so much, about 150V on the plate and:
G1: 0
G2: 62
C1: 1.7
C2: 65

Is this making any sense at all? Safe to say this is a bad design?
I'm not sure if the schematic is exactly right, but there isn't a simple cathode resistor. It is a network of resistors and diodes like that schematic.
 
I'll use the one set of tubes voltages because they seem more useful. Let me know if this looks like what you're measuring.

If the voltages in blue are in the right spots, can you measure across the two zeners circled in red and let me know what you get across each? I doubt its a fundamentally bad circuit, but I suspect something is wrong with this particular unit. It certainly didn't work this badly when new.

1785544966009.png
 
Well I'm out of ideas. The above schematic is not quite accurate. There are 4 4148 diodes. All test good. I replaced 4 current regulators in to-92 packages because I didn't know how to test them properly. There's one zener diode per side that has its negative going to a cathode, and the other side going to some resistors. It tests as ~28V but has 1.2V or so on it in circuit.
 
dunno, nothing I'm seeing makes sense to me. At some point the only sane thing to do is shoot it and change it to a state that has proper documentation. I appreciate a challenge but sometimes it shifts from a challenge to a waste of time.
 
Actually there is a regulator transistor buried in here that is leaking C to E. Will get one on my next parts order.
 
...okay well I thought I was measuring it disconnected enough from the circuit but apparently not. Issue persists with a new part, and old part is fine on diode check completely removed from chassis. Damn thought I had this one figured out.

Okay I need to do some more investigation, might still be onto something.
 
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