[glyphmon]

Because I'm still new at this, I will plan to consult you fine folks when it gets time to need to do the shunt thing to make sure I understand which pieces go where.

As for tube testing not being able to tell you a good tube, but instead a bad one, I'm sure it's analogous to many procedures, like memory testing in computers, in that it only guarantees that a "fail" result corresponds to a bad component.  Even so, I know there are certain units based on their sensitivity that might fail tubes that are otherwise quite usable.  I'll keep on the lookout for a tube tester that hopefully won't break the bank.

If anyone has thoughts about the voltages I listed (traced back to the voltage dividing resistor) let me know.  It looks like 265V going in at the far end of R14 (3.5K ohms) the beginning of the candohm, with 175V coming out at the junction with R15.  I think that's about right.  Given that I measured (in the first round of testing) 172.8 on pin 3 of the 6F5 while it was expecting 170 from the R14/R15 junction, and that's the same source as the 175 I'm seeing heading into R4, but only 61 to 63 at the 6A8 and 6K7, is it likely that, although testing at 21.3K ohm (in-circuit) that this R4 actually is the culprit?  I'm struggling to wrap my head around what I know should be a relatively simple calculation as to how we get from the 175 or so volts on one side of R4 to the other side to a specific value on the other side, headed to the tubes (100 being expected in this case).

Best wishes,
Roy