I removed the C203 leg from R206, and both test to spec. I am soldering PT wires back on then did these additional tests, per amperage recommendation:
We will be working a process of elimination.
Please leave the tubes in and of course the amp off.
We are are going to be making resistance test with the tubes in, but first unhook R226 from where it joins C216C.
Next do the same with R230 where it joins C220.
At the locations where you have unhooked these two resistors make a test from there to ground.
If these two test work out then unhook R228 from C216A and make the same test.
With all of these test your meter should read a brief short and then jump up to a very high resistance.
If you do not read this high resistance then something is loading down that filter node and creating a near short or full short condition.
Please report back with your findings.
I removed the C203 leg from R206, and both test to spec. I must have had a bad reading as they were in the circuit still. I soldered PT wires back on and did the additional tests.
It is worth noting that the oscillator section of the circuit has been entirely removed. Everything in that box on the schematic is gone, including R230 and C220. Clipped at C216C.
Before unsoldering the wire going to the filter cap tube sockets, I just unplugged the filter cap trio C216ABC. I tested resistance from R226 to C216C and R228 to C216A and I get a high resistance, 6M ohms. It then slowly drops down.
That sounds like the expected/normal result? Or do I need to plug cap trio back in and remove wires so C216B stays in circuit?