[Geoff]

I tested the voltages on the 6A7 on all 4 bands to see if the band switch had any issues. Got the same voltages regardless of Band:

[Image: http://i12.photobucket.com/albums/a241/J...2lb2s7.jpg]

Hooked up a signal generator, red lead to grid cap of 6A7 (cap removed), black lead to chassis ground, 460 KHz. I did hear the tone at the speaker loud and clear.

Next I tried putting a second radio next to it, but first I tried it on a working set to know what to listen for. Used my Zenith 9-S-262 set to 1000 and used my TransOceanic B600 and was able to hear the quiet spot around 1460. I verified it was the quiet spot by turning off the 9-S-262 and the regular background noise returned on the B600. I also adjusted the dial back and forth on the 9-S-262 around 1000 and the quiet spot would fade in and out on the B600. Tried it on the Philco 640 and could not hear a quiet spot.