Horizontal lines on a Philips 50pf9830a plasma

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

That looks like a zsus board problem, the one on the left hand side. Possible panel failure?
Take it out and check for cold/bad/cracked solder joints. I would touch everything up with fresh lead solder too be safe. Hamie or reecey will chime in and give better advice.

The zsus is the board that had the bad capacitor? I thought that was called a Y-Main or a Y-SUS or a Y-Sustain board.

I want to make sure I got the terminology right here. The three boards at the top of the TV are buffer boards. The three boards at the bottom are buffer boards. With the TV laying on the floor and the back cover removed, looking down at the TV, all the way to the left is the Y-Main / Y-SUS board and attached to that are the Upper Y Scan Drive and the Lower Y Scan Drive. To the far right, I believe that board is called the X-Main Board or the X-SUS or the X-Sustain board. In the middle of the TV I believe is a power supply board. Then there's the logic board(s). Does that sound about right?

I haven't heard of the Z-SUS board yet. Not sure which one that is.

[ReeceyBurger123]

Re: Horizontal lines on a Philips 50pf9830a plasma

That aint a buffer fault, Xsus seems to be dead IMO. Ipm is probably shot.

[tvtimmy]

Re: Horizontal lines on a Philips 50pf9830a plasma

That looks like a zsus board problem, the one on the left hand side. Possible panel failure?
Take it out and check for cold/bad/cracked solder joints. I would touch everything up with fresh lead solder too be safe. Hamie or reecey will chime in and give better advice.

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

Here's some pictures of the TV turned on for a very brief amount of time. This is after I reseated those cables that I could reseat (not on the upper and lower buffer boards, but the one hooked to the YSUS board that's off to the left if standing behind the TV).

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

If I'm understanding this correctly, I think there's a total of 6 buffer boards, and an upper y scan drive and a lower y scan drive, plus the y-main board. I reseated the cables on the y scan drive boards, because they were easy to get to. Is the y-main board also called the YSUS or Y Sustain board? That y-main is the one that had the bad cap.

Maybe I should remove the metal that hides the lower buffer boards so I can see if there's any bad caps hiding there....

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

I believe the bad capacitor I replaced was on what's called the YSUS board. Is there a chance there's more than just a bad cap that was bad on that YSUS board that might be affecting the buffer board to cause the multicoloured lines?

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

Horizontal lines scream bad upper buffer board to me. Dont run it until you replace it, it could take out the ysus board.

tvtimmy,

We were cross posting. But don't bad buffer boards cause black horizontal lines? How can I verify which buffer board is bad?

I'd also like to add that this customer got the TV for free, on the side of the road, years ago, and paid a place 300$ to fix it. It looks like they replaced some capacitors on a board near what I think are the buffer boards. This is a lot different type of tv than what I'm used to working on, so please bear with me if I don't get all the names of the boards right.

Thanks!

[Spork Schivago]

Re: Horizontal lines on a Philips 50pf9830a plasma

I'm going to try reseating the cables on what I think are called the buffer boards and see if that helps. But from what I've read, a bad IC or a cable needing reseating on the buffer boards will cause black horizontal lines, not multicoloured or rainbow coloured horizontal lines.

[tvtimmy]

Re: Horizontal lines on a Philips 50pf9830a plasma

Horizontal lines scream bad upper buffer board to me. Dont run it until you replace it, it could take out the ysus board.

[Spork Schivago]

Hi,

This is the first plasma I've ever worked on. A customer brought it and there's rainbow coloured horizontal lines going across the screen. I can take pictures if you want to see what that looks like.

I lay it down flat and tear it open. Then I realize it's a plasma and remembered when we bought our plasma, they said not to lay it down flat. From Google, it says the reason not to lay them flat is because the screens inside way a lot and the extra pressure can break them. How do you guys normally work on them? Just be extra careful and lay them down horizontal?

I notice a bad capacitor and think easy fix. There's three boards that look like power supply boards. One is in the middle of the TV, and then there's one each to the left and right. This bad cap was on the to the left (if you're looking at it from where you plug the power in). I replace it. It's a 680uF 25v. I use a 680uF 35v because that's all I had. I turn it back on, hoping the problem would be fixed, but nope. Still has the horizontal lines.

I notice a voltage regulator that looked a little burned next to the cap. I thought maybe that's bad.

The voltage regulator says

ka78
05r

I believe it's a Fairchild voltage regulator. I found a datasheet, but I'm not 100% sure it's the right one. https://cdn.badcaps-static.com/pdfs/...692974ad9c.pdf


According to that PDF though, the fat tab is a ground. If I use that as a ground and put the red probe on the output, my multimeter jumps around as if nothing's hooked up at all. But if I measure the input pin to the middle ground, I get 10V (it bounces a bit), and for output, around 3.5V ~ 3.7V (it bounces a bit). If I measure the fat tab in reference to the middle pin (ground), I get around 9mV. I'm thinking the voltage regulator is testing good.

Anyone with experience with plasmas ever have symptoms like this and have any ideas where I should start?

There's also a few green LEDs on what I'd call the logic board. One of those is blinking green.

I can send pictures of the boards, but there are a lot of boards. So, right now, I'll just upload a picture of the entire TV with the back off and maybe if you guys want pictures, you can just tell me which board, and I'll send nicer pics of that.

The picture with the red box around the capacitor is the capacitor I replaced. Above it, you can see the voltage regulator.

Thanks!