Quote:
Originally Posted by Kevin Kuehn
What you say indicates is that your local oscillator is either not running, or it's running at an incorrect frequency.
When you inject an IF frequency from you signal generator you are forcing the correct signal through the IF transformes, which in turn gets detected by the 30 tube and produces AVC voltage. The key here is you're not relying on the local oscillator to mix with the incoming rf signal to produce that outcome.
In normal operation the rf signal mixes with the local oscillator to create beat frequencies equal to the sum and difference of the two. One of those beat frequencies is the IF signal. You should double check that you didn't replace a cap around the 1C6 tuned circuit with a incorrect value and also verify the two winding's in the oscillator coil(#17484) have continuity.
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Well I checked all of the original "dogbone" resistors in the radio (which are all 1/4 watt resistors according to the service manual) and they are all within spec.
When I recapped this radio, I used orange drops for all but 2 of the capacitors, (the 2 capacitors that I didn't use orange drops on were the .0005 MFD 600 V caps that I had to use Silver Mica caps for because they didn't have any orange drops that went down that low in value), and I made sure that I put the caps in the right spot, so I don't think its the caps or the resistors.
When I first got this radio (and after I realized that someone had attempted to wire a power cord to the antenna wire terminal strip) I had tested the antenna coil and the oscillator coil to make sure they weren't damaged, and they both tested fine.
But then when I was checking voltages around the power switch (where the battery wires wired into the switch), I had accidentally let out some magic smoke but I couldn't tell where it came from, but all I know is that ever since then the antenna coil and the oscillator coil have been reading O. L. on my multimeter, and I'm not sure why because the coils don't look burnt and they don't look damaged either.
Do you need some pictures of the underside of the radio so you can see what the radio looks like underneath and see if you can see anything out of place?