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Is this EHT tranny faulty?

I have a Palsonic 82cm TV which is 4 yo. About 3 months ago, I noticed a low "fizzing" sound coming from the set. The set itself was normal otherwise. Then it started making an arcing sound (crack noise) for the first minute it was on. On a rainy day, this noise started to get louder and was happening every couple of minutes. I shut it down and waited for the humidity to return to normal.

After removing the rear cover, I turned the set on (its live chassis, so I was careful) and noticed a small periodic arc occuring from the stainless-wire clip which is around the EHT tranny to the end of two resistors which are earthed.

In an attempt to stop the arc, I placed a plastic insulator in the gap (which is about 3/16"). This stopped the arcing, but caused a return of the fizzing noise. The set is still normal except for some picture interference from presumabley the RF radiation.

Has this EHT tranny failed with insulation breakdown in the windings near a crack in the potted-case of the tranny? Or is it a case of the clip acting as the electrode of a capacitor, charging up, then discharging to ground. The EHT diode appear to be inside the EHT housing.

thanx for any opinions.,, Jason

Reply to
Jason James
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Suspect the tranny itself. Don't let this condition carry on, as much more serious trouble will result. These types of arc typically zap ( expensive ) ICs elsewhere in the set, or corrupt the contents of the EEPROM that stores all the adjustments and settings ...

Get the problem fixed, sooner rather than later.

Arfa

Reply to
Arfa Daily

otherwise.

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Thankyou very much for that information. This set wasn't cheap ($1200 Australian) and I would like to get 3 more years from it before we go all digital.

regards,..Jason

Reply to
Jason James

Get some good silicone gasket sealer. With the set off & unplugged (duh). Goop that area up where it's arcing from....apply plenty! Let dry 24 hours and you should be OK

-- ========================== Jeff Stielau Shoreline Electronics Repair

344 East Main Street Clinton,CT 06413 860-399-1861 860-664-3535 (fax) snipped-for-privacy@snet.net ========================
Reply to
Shoreline Electronics

While it is possible that the HV is arcing to the transformer ferrite core where it then arcs to those two resistors, this would mean replacing the transformer is the proper and safe fix.

On some tv sets, the flyback transformer core get grounded underneath the flyback through a spring clip and a solder connection. If the ground fails the capacitvely coupled high voltage static charge can build up in the metal of the core and it will arc over to the nearest low potential component.

I am betting on number one as the fizzing sound is probably the high voltage arcing to the core where you cannot see it.

Reply to
dkuhajda

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