Pn42a450p1d

[ljintexas]

No standby..totally dead. Found F801 and FS801 fuses blown, MOSFETs Q801 and Q802 shorted. The IC that drives the MOSFETs, U804, has several pins grounded that should not be according to fact sheet. Also found several bad diodes nearby. Did something else cause this or is this normal wear and tear on the SMPS for an 8 yr old plasma?
Thanks

[ReeceyBurger123]

Re: Pn42a450p1d

You might want to consider replacing the primary filter caps, ive had a similar issue where the primary caps dry out which blows the pfc diode which blows the main transistors and there respective ic's.

[ammarben]

Re: Pn42a450p1d

give us the model of power supply BN44...

[ammarben]

Re: Pn42a450p1d

U804 mc33067 pin15 vcc ,pin 4,13 gnd

[ljintexas]

Re: Pn42a450p1d

BN44-00206A
According to the specs on the IC it's rated for 150 deg F..
Main filter caps are barely in spec for capacitance. Pass ESR test easily.
I bet you are correct. By the time I buy all needed components with frieght, I will spend $40
I can get a replacement with one year guarantee for $45.

[ljintexas]

Re: Pn42a450p1d

I took the main filter caps out of circuit..One passed ESR and capacitance both. The other one failed both tests. You were right on the money Reecey!
I ordered the replacement board with freight it was $53.

Thanks for your advice!