Vox AC30C2

[pnut5150]

Pin 3: 48.1k
Pin 8: 48.1k

[g1]

No R60 voltage does not seem right. Phase splitter tube does not seem to be conducting. Can you see both sides heaters lit up in phase splitter tube?
But you asked about D12, which brings up a good point, that we should make sure the power supply voltages are good before anything else. On AC volts you should have around 25VAC between J42 and J43. And check that F3 resistance is good.

[pnut5150]

Where is f3 I can't find it? The wire on the on-off switch from ac has something sticking out of it...are there a fuse or something in there?

[pnut5150]

Two ceramic caps wired in from mains to switch

[g1]

F3 is a 2.2 ohm resistor, connected between J43 and D12 anode.
No idea what is connected to the switch, schematic shows surge protectors.

[pnut5150]

F3 is good 2.2 ohms
J43 has 26.15 ac
J42 has 0.003 ac
I was reading d12 and d13 in dcv is that correct?

[pnut5150]

Both sides of phase inverter are lit, all the other tubes are lit as well. I did notce than the blue glow in the power tubes wit. Trem on dims n and out with the trem...I guess that's Norma though .

[g1]

Yes, read DC at D12 & 13. Should be +27VDC at D12/R106 junction, -27VDC at D13/R103 junction.

[pnut5150]

J42 & 43 tested between the two are 26v, I read them individual awhile ago. Should d4 have a high voltage side?

[g1]

Please try to stick with one thing at a time . D4 is a diode bridge for the heaters. You said heaters are all lit so D4 is no big concern right now.
How about that + & - 27VDC at D12 & D13 ?

[pnut5150]

Power tubes seem to be extremely hot to me, here are voltages on power tube beside phase inverter are:
Pin 1: starts from 0.00mv and goes to 400mv and starts all over
Pin 2: floats from 006.1-011.9mv
Pin 3: 7.92v
Pin 4: -012.1mv
Pin 5: -012.3mv
Pin 6: floats through mv
Pin 7: 323v
Pin 8: floats through mv
Pin 9: 301.9v

[pnut5150]

Sorry I was getting to far off reservation lol!
Ok d12 has 33.25v on banded end and -21.8mv opposite end
D13 -022.6mv on band end and -33.10v on other end
R106 32.91v & 27.83v
R103 -33.09v & -28.52v

[g1]

Ok, +/- 27V sound close enough.
Find a way to turn off the trem, with footswitch or whatever, I think that is giving you the pulsating voltages at power tubes.

Might as well continue with power supply, what are DC voltages at B+1,2,3,4,5 ? Can measure at R120, R74, R22, R15.

[pnut5150]

R120: +331.1v & +307.9
R74: +307.7v & +225.8v
R22: +225.1v & +190.2v
R15: +189.7v & +173.6v
Is that proper way to check them? Reading on each end?

[g1]

Yes, reading on each end will be fine. R120 is a big 10watt resistor, it may be white rectangular or some kind of heatsink type mounted on the chassis somewhere. But you can measure instead at the banded end of D7 or D8. This will be B+1. The other values you gave will be B+2 (308V) and so on down in descending order.