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Car radio failure? (very strange)

Hi everyone,

since a few days ago I cannot listen to any of the FM stations. Here is what I could notice:

-MW & LW are OK

- FM sometimes works, but not for a long time (10 sec - few minutes)

- just before loosing an FM station, there is a time period of about 10 sec during which 'input level indicator' slowly arises towards the maximum and in the same time the station fades out - afterwards, there is only a silence

- after the station fades out: if I use a preset FM station, there is a 'full signal' indicator on the LCD, but if I try 'search', searching starts and it searches for the infinite time (going all around through all FM scale)

- if I am listening to a MW or a LW for a certain time period: then FM is OK, but only for a certain time period

- longer the time period of listening to a MW or a LW station is, longer I can use FM mode (no joke :-) ) before it fades out as described before

I have checked the antenna and other junctions. Does anyone know where could the problem be? Could it be a capacitor (the fading pattern makes me think something is slowly charging, something like an RC node). Or maybe a PLL module? Just guessing.

ps Sorry about my English

Thank you,

--
Chupo
Reply to
Chupo
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The signal indicator is most likely derrived from an AGC line. The fact that it indicates full signal might mean the AGC is going to minimum gain, when it does not need to be. There is likely to be different AGC stages for the FM section to the AM section, as different IF gains would be used.

Reply to
Dave

Sorry, I mean different IF stages on different frequencies. The gains might be different, but the main point is the IF and AGC will most likely not be common.

Reply to
Dave

Do you think it could be repairable?

Thanks for answering me,

Best regards,

--
Chupo
Reply to
Chupo

Try posting to sci.electronics.repair.

Reply to
Walter Harley

Yes, I have already done that and I've got some useful information also.

Thank you,

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Chupo
Reply to
Chupo

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