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Interesting FM Problem

On a forum, I read this :

"I am the proud new owner of a 2270. It seems to be in pretty good shape, b ut I noticed today that it seems like all the radio stations at once are co ming from the left channel. The volume knob doesn't affect it, as it is the same level no matter where you turn it to. Changing the input selector doe sn't help, and neither does moving the tuner. What is going on? "

The thread contiues with some details, these are FM stations. I can underst and if it is AM, but FM ? He says it is about ten stations all at once, tho ugh that is probably subjective, it could be "only" five.

What, in a regular audio reciever could demodulate multiple FM staions up i n around 100 mHz that have a measely 75 kHz deviation ?

Could this have something to do with this digital stuff in the signal now ?

Reply to
jurb6006
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Sounds more like local taxis breakthrough on the power amplifier to speaker lead. A signal that doesn't depend on the input selector or volume control isn't going through either!

I can't see any way that normal FM channels could appear only on the left channel of a stereo pair. In all the places I know they transmit stereo as L+R and L-R except in Japan during bilingual news transmission. (When L+R = Japanese and L-R = English)

I shudder to think how this could happen as described unless there is something else present causing massive intermodulation distortion.

--
Regards, 
Martin Brown
Reply to
Martin Brown

e, but I noticed today that it seems like all the radio stations at once ar e coming from the left channel. The volume knob doesn't affect it, as it is the same level no matter where you turn it to. Changing the input selector doesn't help, and neither does moving the tuner. What is going on? "

erstand if it is AM, but FM ? He says it is about ten stations all at once, though that is probably subjective, it could be "only" five.

up in around 100 mHz that have a measely 75 kHz deviation ?

ow ?

Maybe the positive feedback valve is misbiased, causing frequency drift of the tuning tank :)

NT

Reply to
meow2222

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