Hello All,
This radio is the same one that had the strange problems before. It has come back to haunt me. All of a sudden now, the filament in the IF amplifier tube is bypassed. There can be no tube in the socket and the rest of the tubes' filaments and dial lamp light up. There is an open if I measure from pin 2 to 7 on the socket for continuity with no tube in the socket. This is very weird. The circuit is open. How can the filaments be energized when there is an open in the string? I have gone over it several times. It makes no sense. There is some sort of strange magic going on. Where should I look for this bypass? I'll keep checking. If anyone has some ideas please help.

Thanks,

Dave

Hello Again,
If I have both the 12SQ7 and IF amp out, I still have lit filaments. This is too weird. However, when the 12SA7 was in the socket, it's pin 2 was magically connected to B-, thus ending the filament string a bit short. When I replaced the 12SA7, the radio came back to life. Somehow the filament got shorted to the cathode.
This was very interesting.

Dave
:Hello All,
: This radio is the same one that had the strange problems before. It has come back to haunt me. All of a sudden now, the filament in the IF amplifier tube is bypassed. There can be no tube in the socket and the rest of the tubes' filaments and dial lamp light up. There is an open if I measure from pin 2 to 7 on the socket for continuity with no tube in the socket. This is very weird. The circuit is open. How can the filaments be energized when there is an open in the string? I have gone over it several times. It makes no sense. There is some sort of strange magic going on. Where should I look for this bypass? I'll keep checking. If anyone has some ideas please help.
:
:Thanks,
:
:Dave