Author Topic: re: a audio feed back loop in a Radio Shack cb radio  (Read 1256 times)

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Offline reble

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re: a audio feed back loop in a Radio Shack cb radio
« on: April 26, 2019, 06:16:28 AM »
This is in a Realistic TRC-474 CB transceiver.  The receiver is making an audio tone in it when it is turned on. The dash panel lights turn on and the TX is showing 5 watts out on my swr/power meter. But the same tone is in the TX modulation when I have a CB HT turned on, on the same ch. I keep the CB HT as a test radio.  The RF gain and the squelch have no effect. The tone goes away in PA mode. The PA mode works fine.  I don't know where to find a service manual for this radio.

Now I have an AA degree in general  electronics. But I primarily fixed electric/electronic typewriters, fax machines and 1st gen to 3rd gen copy machines. I am also a Ham Radio Operator. I probably could fix this CB radio if I had the test equipment. All I have in the way of test equipment is an Ideal 61-340 VOM and an old Echo portable tube checker. I dabble in restoring old tube radios with my room mates help. Now I can't go sticking a probe in the radio with my shaky hands, I have micro  tremors in my hands and I would probably short out something, that's why I had to retire. But my room mate knows enough electronics to be my hands, I tell him where to stick the probe. But without more test equipment and the service manual. I would only be guessing. I could use some help please.