Zenith Z50PT320

[thekiltman85]

Good afternoon,

I have a Zenith Z50PT320 TV that would click on then immediately back off. I systematically removed boards 1 by 1. When I removed the Ysus board and buffers the PSU stayed on consistently and no longer power cycled. I ordered a new Y sustain and Y buffers, as well as a new PSU. The new PSU was DOA but I installed the new buffers and y sustain board on the old PSU and the TV came on and stayed on power wise, however there is still no picture. The screen stays black and does not flicker. The TV appears to be in standby mode because the LED on the front is red. I can't verify if the TV has sound because I can't figure out how to switch the inputs to our roku device. We do not have cable. All told I need to buy a new multimeter and take readings I'm sure but i'm pretty amateur and just getting into this as a hobby. Any thoughts? Attached please find pictures of the inside of the TV.

Best regards and happy hunting,
Aaron

[thekiltman85]

Re: Zenith Z50PT320

I take it back. There is audio now on the TV just no picture. I'll check the ysustain board and Y buffers with a new multimeter hopefully some time this week and give an update. I have a hard time believing this board will be broken as the seller seems reputable and because I also received from another seller a clearly dead psu. Can I be that unlucky? What else can I try? Thanks again

[tom66]

Re: Zenith Z50PT320

Check all voltages, Vs, Va, Vsc, -Vy and Vzbias.
Low Vsc/-Vy: isolate Y-buffer and test again. If voltages come back that indicates that buffers are likely shorted.

[thekiltman85]

Re: Zenith Z50PT320

Voila. Thanks for the advice. As it turns out I had ordered a replacement Y sustain board and buffers. The buffer boards ended up being as you said shorted. I used the new y sustain board, and old buffer boards and so far so good. I'll have to run it for a bit and see if the repair takes. As it stands right now the set works like brand new. Thanks again!