46-1209 if cans - Printable Version
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46-1209 if cans - philco4me - 03-16-2014
My 46-1209 gets no radio at all on any band. The amp is very strong. My gut is that one of the if cans are bad. I have a donor chassis so is it ok to swap the if from the donor chassis ?
RE: 46-1209 if cans - Mondial - 03-16-2014
Why do you think the IF transformers are at fault? Did you check the windings for continuity?
How do the operating voltages on the tubes compare to the readings listed on the schematic?
Honestly, there are many things that could cause no reception and a bad IF transformer is probably the last place I would look.
RE: 46-1209 if cans - philco4me - 03-16-2014
When the radio was working it slowly faded out. I used to adjust the if next to the 7f8 to get it back until that did not work anymore I replaced the 7f8 and both 7h7 but still no luck
RE: 46-1209 if cans - Mondial - 03-16-2014
Have you changed any of the paper capacitors or power supply electrolytics? Fading out could be caused by high leakage causing the output tubes to draw excessive current.
I would check the power supply voltages and change any critical capacitors before proceeding any further.
RE: 46-1209 if cans - philco4me - 03-16-2014
I have replaced all the caps
RE: 46-1209 if cans - codefox1 - 03-17-2014
Agree, you might have one or more carbon resistors that have drifted high and may cut out completely when power is applied. Mayn now just replace all of them whilst doing the capacitor replacements. Of course, poking around with a chopstick might discover a mechanical flaw as well. Otherwise work bakwards from the audio to the antenna to find the malfunction.
RE: 46-1209 if cans - Mondial - 03-17-2014
Here is the service info for your radio:
http://www.nostalgiaair.org/PagesByModel/586/M0013586.pdf
There is a chart which gives all the voltage readings for the tube socket pins when the radio is operating properly. Compare these readings to yours to try and localize the problem.
As Codefox said, a bad resistor could cause your symptoms. Voltage checks should point you in the right direction. I would check around the 7F8 tube first.