Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

[advent35]

Phillips 50” Plasma 50pfp5332d/37

I began with capacitor problems on the power supply, y main and x main(click click click), unit now starts and goes into protect mode. Traced problem to y main short to ground on the Vs circuit. I have found at least one of the 88N30W FETs shorted on all 3 legs and suspect others (I have only removed the one) and have ordered a kit to replace them. My question is could these FETs be the cause of my problem or should I look farther? I found a diode I suspect is bad also, can they be tested in the circuit?

attached pictures of y main part number and diode (ZD5101 location)

Thank you in advance for any help.
Jeff

[tom66]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

They can cause the fault. Also check the Y-buffer upper PCB for a burnt/damage buffer IC. Common fault is for that IC to fail, which can damage Y-main, or Y-main failing which can damage the IC.

[advent35]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

I tested the Y buffers, no visible damage to the IC's and could not find a short when tested with meter. That is if am checking the buffer correctly. I watched a video on YouTube for testing a different model buffer board and think that I have the right idea. From what I've read on here I think that it maybe your video (ubuntututorials).

[tw2005]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

I'd double check. by far the most common fail is shorted upper/blown ymain.

Might be some useful info in here. shows how to test ymain with out the buffers and how to do a quick test upper + lower combined.

[advent35]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

Thank you for the response and information. My buffer is a one piece board would the test points be basically the same or would you have instructions for the one piece y buffer board?

attached part number below;

[advent35]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

Tested from CN5407 PINS 1-24 to CN5401, CN5402, CN5403, CN5501, CN5502, CN5503.
The outer 6 pins marked in yellow on either end of all 6 of the connector are open loop, the others in red all test around .55 volts.

Is this normal?

[tom66]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

If you reverse it and get open circuit, that is OK.

[advent35]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

Yes the pins marked in Yellow are all open circuit with leads reversed.

I want to thank you both for all your help!
This is my first attempt at TV repair.

[tom66]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

I meant the red points. They should be OL with probes reversed. Yellow are not connected.

[advent35]

Re: Phillips 50” Plasma 50pfp5332d/37 Vs short to ground

I understand now, Thank you!