This 19" Samsung TV doesn't turn on anymore. I check secondary voltages, none. Nothing shorted there. 320V in primary side, OK. Nothing looking bad at that side either.
I think about replacing photocoupler and 431 regulator. When I unsolder PhotoCoupler I notice what I call "creeping metallization" in PCB, between two PC legs (can't remember if it was in primary or secondary side). Then I look closely at photocoupler and there's an evident metallization between two legs!! Clean it with IPA and brush, and the problem is gone!
Then, so far, I've detected "creeping metallization" in:
-Inside tact-switches, producing random self-activations, typically in TV manual controls ("volume rises itself", "changes channel itself"...).
-IR receivers, between legs.
-Photocouplers, between legs, producing bad regulation or dead PSU.
But the worst metallization I've seen was in an old equalizer (Vortex FX707P). See pictures. What's the scientific name of this chemical reaction? Why it happens?
I think about replacing photocoupler and 431 regulator. When I unsolder PhotoCoupler I notice what I call "creeping metallization" in PCB, between two PC legs (can't remember if it was in primary or secondary side). Then I look closely at photocoupler and there's an evident metallization between two legs!! Clean it with IPA and brush, and the problem is gone!
Then, so far, I've detected "creeping metallization" in:
-Inside tact-switches, producing random self-activations, typically in TV manual controls ("volume rises itself", "changes channel itself"...).
-IR receivers, between legs.
-Photocouplers, between legs, producing bad regulation or dead PSU.
But the worst metallization I've seen was in an old equalizer (Vortex FX707P). See pictures. What's the scientific name of this chemical reaction? Why it happens?
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