[glyphmon]

MrFixr55,

You nearly had me thinking I'd forgotten a step there when you included "chassis ground" in the order of the voltage dividing resistor.  Yes, these are in the correct order, and I migrated and/or replaced one wire at a time when wiring the new assembly back in to ensure I didn't miss any, including the connection to chassis ground at that R16/R18 junction (not R16/R17).  An aside, I'm not sure why they went R14 <-> R15 <-> R16 <-> R18 <-> R17, but it is marked as such on both the diagram and schematic, and so that is how I recreated it.

I'd need to place an order to get an actual 22K ohm.  I have some 10K, 30K, and 50K on hand.  For testing purposes, two 10K in series should be an acceptable test to see if there's a difference, right?  The current R4 is testing at 21.1K out of circuit.

Edit/Update: I went ahead and tried two 10K in series, tested to 20.2K out of circuit, removed original, put in the two in series and no significant change.  64.6V on pin 4 instead of 63.5 off of 176V coming out of C16 (170V expected), so it looks like the original R4 was functioning approximately as intended at least.  I think I'll put that one back in.

What do you make of the voltages I measured when pulling one/the other/both tubes?  Even if it doesn't get us any closer to the answer, I'd be curious to know the implications of each.

With the 6A8 removed, the 6K7 showed 138.7V on pin 4, instead of 63.5 previously measured (100 expected).
With the 6K7 removed, the 6A8 showed 107.2V on pin 4, instead of 63.5 previously measured (100 expected).
With both 6A8 and 6K7 removed, the voltage on the tube-side of C15 and R4 is 218.  I also went back to check and yes, same voltage on either side of the resistor in this case.

We can shelve the idea of switching power to the RF section for the time being.  There's been a lot of good information shared and I will definitely refer back to this thread when we get to that point.

Best wishes,
Roy