Sony PFM-42X1 - Doesn't Turn On

[Ritalin]

Greetings All!

I'm debating if I want to tackle this TV or not. As soon as I opened it up I nearly 'ed. I've never seen so many caps on a power supply in my life. And since it's more of a 'display' monitor and not so much TV, I don't know what the market for this type would be like.

When you press the power button, you hear the famous 'click' but nothing comes on the screen (it doesn't even light up). And I hear a buzzing sound out of the board on the right and there's a small fan on the board on the left, and that doesn't even turn on. So maybe power supply issue?

If anyone thinks this is worth repairing I can get closer board pics. But I don't know if I want to recap this power supply.

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

I'm pretty sure this is a 480p plasma so not HD capable. Are the caps bad on the PSU?

[Ritalin]

Re: Sony PFM-42X1 - Doesn't Turn On

Just a visual inspection, I don't see anything wrong. They are even Rubycon caps. But with that many so close, I'm sure it got hot in there and they're dried out.

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

No, they're probably fine. Your problem is likely on Y-sus or Z-sus, left and right boards in your photo. Unplug one at a time and see if TV will stay on. No picture is expected when Y-sus is unplugged. Dim/poor image only with Z-sus unplugged.

[Ritalin]

Re: Sony PFM-42X1 - Doesn't Turn On

When I unplugged the board on the left (Y board?) it did the same thing as before. But when I uplugged the board on the right, the power supply did more clicking than normal. And eventually the power button became non-responsive.

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

Using your DMM, try to test the VS and VA out of the power supply. The connectors should be labelled. Try with both connected and with both disconnected.

[Ritalin]

Re: Sony PFM-42X1 - Doesn't Turn On

Values are all good, and thankfully Sony did a nice job labeling the voltages, so it was easy to verify everything, but I did come across a bad fuse on the Z-Board, so those have been ordered and will be here in a couple days.

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

This is basically an LG plasma inside, with a few Sony bits. One of LG's first commercial PDPs. You've got a good history piece, at any rate...

[Ritalin]

Re: Sony PFM-42X1 - Doesn't Turn On

So I pulled the fuses from another TV and it works! But the YSUS board is still making an awful buzzing sound... Any thoughts?

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

Nice one. Horrible buzzing is normal. Maybe add a little glue if you want. Putting the case on will usually eliminate 95% of it.

[Ritalin]

Re: Sony PFM-42X1 - Doesn't Turn On

Eh... it's REALLY bad... and I think I don't have full control over the TV. When I go into the menu I can't select some things.... I'll look into it more once I get the board out and see if I notice anything weird.

[tom66]

Re: Sony PFM-42X1 - Doesn't Turn On

If you've got the frame off the TV will always buzz louder than normal.