Radio working and then put away , stored indoors for some years. Now only strong AM signals come through with a decent aerial. The IC functions as far as remote tuning via varicap , AGC , S meter, but what could decrease the RF gain just sitting around unused ? I have the Sanyo datasheet and DC supply to the RF section is correct
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
"N_Cook" wrote in news:g1e72n$ei0$1 @registered.motzarella.org:
Possibly capacitor aging. Ceramic capacitors 'AGE' (decline in capacitance with time) High K ceramic capacitors 'age' at a higher percentage rate than low K capacitors, so ceramic 'bypass' capacitors can decline in value with time.
You could 'deage' the capacitors by heating the radio above the ceramics Curi point. see
If you stored in humid conditions, fungus could grow, metals corrode, electrolysis form paths across circuit boards. All of those can effect gain also.
-- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
N_Cook schrieb:
Have a look at C 102 (47 nF at pin 2).
HTH
Reinhard
Common sense dictates that the IC isn't going to fail just sitting around. Think of what other components usually fail with age???????????????????
Maybe a bad voltage into pin 17 (AGC input)? Possibly one of the filter electrolytics on the detector-to-AGC path has dried out or gone open?
--
Dave Platt AE6EO
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