JO47BAIRD power problem

[dick_barton]

Re: JO47BAIRD power problem

It could be one of the mosfet on the circuit board or even one of the capacitors but they are under the metal shielding so I would remove the shield for this test.

[vinceroger69]

Re: JO47BAIRD power problem

It could be one of the mosfet on the circuit board or even one of the capacitors but they are under the metal shielding so I would remove the shield for this test.

+1 as you say can be any part on these boards causing the issue

[cvel]

Re: JO47BAIRD power problem

Its running OK with no back on it by an open window but transformers on the inverter boards are 64 degrees power board 30 degrees but the screen is testing 34.7 degrees which seems a little hot to me but I'm no expert in this field. I'll remove that metal shielding from them caps and test again shortly and let you know. Thanks again for your help

[cvel]

Re: JO47BAIRD power problem

Another update ive put the back onto the TV as it was working OK once back todlgether I plugged back in and tried to turn it on the screen flickered on I heard walhat sounded like a spark type noise then it went back onto stand by I left it 15 minutes tried again and all is working again.

[vinceroger69]

Re: JO47BAIRD power problem

that spark noise could be from a few places but as you have found heating that one invertor board makes the fault appear quicker maybe there is a fault on that board as it makes the high voltage (and could make a spark like noise) as its for the ccfl tube voltage but in the mean time as you have had all the boards out make sure theres no trapped wires under them and make sure all the ground screws are tight.

[cvel]

Re: JO47BAIRD power problem

Thanks for the advice. Are these boards repairable I repair kitchen appliances for a living so I'm OK with a bit of soldering if needed. I read on another site someone had very similar symptoms with a Toshiba TV and it was dry solder joints in the inverter somewhere soon as the kids have gone to bed I'll check all this but I don't understand how dry joints would create excessive heat this TV didnt cost me anything so I'm happy to have a play about with it and if needed spend a little on getting it going.

[vinceroger69]

Re: JO47BAIRD power problem

These boards are usually really cheap on ebay etc sometimes its just not worth repair if you have a esr meter you could test the capacitors for uf and esr as maybe failing with the heat on that board a spark noise could be from a winding on the transformers i guess if breaking down etc, hopefully budm or dick-barton may have more ideas too regarding this fault im still learning so others with more experience may have other tests etc.

[dick_barton]

Re: JO47BAIRD power problem

Inverter transformers sometimes need to be re-soldered but also check the electrolytic capacitors on the board.