Quote:
Originally Posted by bob91343
It's time to stop groping and do some serious troubleshooting.
First make sure the local oscillator is running, and covers the proper frequency range. Put a signal into the IF and see if it has reasonable gain. After that, you will have enough info to track down the problem.
Generally, you won't find that the 12AT7 functions on AM. You probably have something like a 6BE6 or 12BE6 for the front end on AM.
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Bob, I appreciate your tips and advice, but I do not have any test equipment except a digital multimeter (gave up my workshop years ago when I moved here
), so I cannot do any kind of signal tracing or advanced troubleshooting beyond soldering bad connections, replacing tubes, etc. I would not know how to test the local oscillator in the radio, either, without test gear.
The converter tube in the C845 is a 12AT7, which functions as both oscillator and mixer stage. The RF amplifier, which functions on both AM and FM, is a 6BJ6.