If the meters are to be trusted on pins 3 and 6, then I'll quit fretting about them, since the meter readings match the specs and the waveforms are shaped correctly.
The final question concerns pin 7, the other grid, where the waveform looks correct (per Philco manual) but the voltage looks low, less than -1V where the manuals call for -3.2V to -3.5V.
http://antiqueradio.org/art/6DR7Pin7...ystVoltage.jpg
http://antiqueradio.org/art/6DR7Pin7FlukeVoltage.jpg
As I understand it, the pin 7 grid returns feedback from the pin 1 plate. I have replaced the K5 couplate, which does the returning.
I also replaced capacitor C43 (.0015/1KV) by wiring two .00033/630V caps in series to make one .00165/1260V. Since then, I got a ceramic .0015/1KV cap which I could substitute for C43 if the difference between .0015 and .00165 seems that critical. (Only a 10% difference, right?)
On that part of the tube, the plate voltage on pin 6 is correct and the cathode voltage on pin 8 is in the ballpark (actual 6.5V; Sams 7.5V).
Beyond that, I'm back my original question whether the output transformer is bad. I ordered a replacement from Moyer, so I'll soon be able to test that by substitution.
Regards,
Phil Nelson