My Philco seems to have no signal from the osc. tube; all voltages on the 7C5 osc. look ok. Radio works with 900KC from sig gen to grid of 7A4 converter. I don't have an O scope to check osc output. Looking at broadcast only.
Any ideas appreciated.

Hi Allan

Check continuity of the oscillator coil. Philco has problems with coil corrosion which causes an open.

There are a couple ways to check the osc. 1. Check voltage on grid #1 of the oscillator tube. It will be several volts negative when oscillating. 2. Tune your radio to 1000. With a second radio nearby you should be able to pick up the osc signal at 1455.

http://www.nostalgiaair.org/Resources/487/M0013487.htm

Norm

:My Philco seems to have no signal from the osc. tube; all voltages on the 7C5 osc. look ok. Radio works with 900KC from sig gen to grid of 7A4 converter. I don't have an O scope to check osc output. Looking at broadcast only.
:Any ideas appreciated.
:

Hi Norm,
Many thanks to you; your diag. was right on; upon re checking the osc coil, found that it had a broken winding. fixed and working fine now.
Allan

Hi Allan
:
: Check continuity of the oscillator coil. Philco has problems with coil corrosion which causes an open.
:
: There are a couple ways to check the osc. 1. Check voltage on grid #1 of the oscillator tube. It will be several volts negative when oscillating. 2. Tune your radio to 1000. With a second radio nearby you should be able to pick up the osc signal at 1455.
:
:http://www.nostalgiaair.org/Resources/487/M0013487.htm
:
:Norm
:
::My Philco seems to have no signal from the osc. tube; all voltages on the 7C5 osc. look ok. Radio works with 900KC from sig gen to grid of 7A4 converter. I don't have an O scope to check osc output. Looking at broadcast only.
::Any ideas appreciated.
::
:
: