Quote:
Originally Posted by kbmuri
Volume at max, not one peep of audio signal. I even turned the generator's tone modulation on, set it at exactly 65.75 MHz, and tuned the slug for maximum sound. Turned the generator off, STILL no audio. The generator tone is apparently only getting thru because it's AM. Completely assuming the audio of my Rat Shack receiver is accurate, at 65.75 MHz, and present. Just doesn't get thru the system. Only difference is AM vs. FM.
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Another thought, using another TV set, see if you can "jam" the sound carrier with your signal generator, at 67.75MHz. Only a few dB stronger signal on the sound carrier should be enough to achieve "capture" of the FM detector, thus blotting out the normal sound signal. You should hear only a faint detection of the generator's AM modulated signal on this other TV set. And if you have the set under repair also receiving the same TV channel (or the VCR RF output) and see the same video and hear the generator's modulated AM, I'd suspect that the FM detector is somehow misadjusted or broken and can only hear AM and no FM. That would be the final sound transformer. If you can tweak the detector for max AM detection, and the VCR sound carrier is jammed on the other TV, try turning off the generator and try tweaking the detector to see if you can get some FM sound.