I have a quad fm4 tuner (recently acquired) Had the typical leaking battery corrosion which while it didn’t take out any parts damaged the ground plane on the top side. I have taken the battery off for now. After replacing the corroded socket for ic1 - also corroded on pin 28 - and cleaning thoroughly with ipa it works nicely. But..
While the stereo light flickers as I tune up the fm band it doesn’t light for any station I tune too. The tuning bars show a strong signal so it should be receiving a good stereo signal. Would this indicate the stereo decided chip is bad? The sound is fine but I’m guessing it’s mono. Any help on resolving would be appreciated
While the stereo light flickers as I tune up the fm band it doesn’t light for any station I tune too. The tuning bars show a strong signal so it should be receiving a good stereo signal. Would this indicate the stereo decided chip is bad? The sound is fine but I’m guessing it’s mono. Any help on resolving would be appreciated
Look into the multiplex decoder circuit. See if you get the 19kHz pilot tone on stereo stations.
But do not attempt alignment yourself.
https://www.meridian-audio.info/public/quad_fm4._tuner._wsm._a6481[1669].pdf
But do not attempt alignment yourself.
https://www.meridian-audio.info/public/quad_fm4._tuner._wsm._a6481[1669].pdf
Surely you can tell whether the sound is mono or stereo? Does it change if you put the preamp into mono mode? If not, it’s mono, so you need to tweak RV6, near IC17 (TCA4500 or LM4500) until you get stereo, then adjust it to the midpoint of the two extremes between which you still get stereo, as shown by the stereo light.
Very unlikely to be the chip, and very unlikely that any further alignment is required.
Very unlikely to be the chip, and very unlikely that any further alignment is required.
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