HP PL4260N Damaged Y-Sustain

[rpgruss]

I picked up this TV on craigslist, another victim of no picture. Turns out the IPM was shorted, installed a new one and plugged it in. When I turned the TV on, it did the strangest thing: the picture was pulsing on and off. I started checking voltages, and all power supply voltages were present and accounted for. By the time I was done checking voltages, the picture was no longer flashing and I was bathed in the blue 'No Signal' screen.

Suddenly, I noticed smoke emanating from my freshly repaired y-sustain board. I pulled the power and inspected the damage. Oddly, the smoke was not coming from the IPM chip, but rather from one of the two 'cards' at the bottom of the board.

Turns out, the previous owner had screwed the base to the tv with screws that were far too long. So long in fact, they drive into the card, damaging the transformer (And managing to partially uproot it!)

Does anyone know what kind of transformer this is, so I can source a replacement? Or even a replacement card I can solder in? Thanks!

[PlainBill]

Re: HP PL4260N Damaged Y-Sustain

The transformer has an LG part number, the power module hand another LG number. Your best bet would be to try to find a dead 6871QYH053B and cannibalize it.

PlainBill

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

That's what I was afraid of. I see a few people offer a repair service, I think I'll contact them and see if they have any bad boards they would be willing to part with.

[start2011]

Re: HP PL4260N Damaged Y-Sustain

I have Y-board (6871QYH053B and X-board (6871QZH056B from Toshiba 42in. Y-board, large IC under black heatsink was bad. I ordered 2 large ICs STK795-821 and 2 fuses to replace both of them . One for Y-board and another one for X-board. I think yours has a problem like mine.

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

start2011, are you referring to the flashing screen? I've already replaced the IC on the y-sustain board, could the x-board have a bad IC as well?

[cmj21973]

Re: HP PL4260N Damaged Y-Sustain

ebay:
auction
http://www.ebay.com/itm/Y-SUSTAIN-68...item43acd44c59

buy
http://www.ebay.com/sch/i.html?_from...All-Categories

Is the transformer the only thing damaged?

[PlainBill]

Re: HP PL4260N Damaged Y-Sustain

start2011, are you referring to the flashing screen? I've already replaced the IC on the y-sustain board, could the x-board have a bad IC as well?

Both boards are prone to failure, but the symptoms are different. Given the display you had I would say the Z-Sustain is good.

Your idea of contacting those offering a repair service seems like a good idea.

PlainBill

[start2011]

Re: HP PL4260N Damaged Y-Sustain

start2011, are you referring to the flashing screen? I've already replaced the IC on the y-sustain board, could the x-board have a bad IC as well?

TV shut down in 1/2 second when power on. I, checked caps and fuses, found two 4A fuses were blown. One on Y-MB and the other one on X-MB. I changed both of them and power on TV again, power stayed, fuses no blown but no picture. I did`nt check sound. I measured output voltages from power supply to Y-MB and X-MB were ok... I pulled ICs, found one was blonw. You can see pichttps://www.badcaps.net/forum/attachment.php?attachmentid=34913&stc=https://www.badcaps.net/forum/attachment.php?attachmentid=34914&stc=1&d=13281584951&d=1328158478s.

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

I found a defective board on eBay, it is on order and should be here in the next few days. In preperation, I tried to remove the sub-module, which turns out it is next to impossible. I used desoldering wick, hot air, even chip quik out of desperation, but it will not release! Turns out it is moot anyway, as an inductor on the board itself is also damaged. That knucklehead completely trashed the board by using screws that were too long!

Oh well, hopefully the one I ordered just has a bad IPM, otherwise it is off to China for me, and lots more $$$.

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

Got the ebay board in, and turns out it's problem isn't the IPM. It tests good. No shorts between Vs and Ground or Va and Ground. It was missing a fuse but I have plenty of those.

What was wrong was the P8 connector is damaged, and a capacitor was knocked off next to it. Should be able to swap them over from my old board.

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

I'm back, with a new problem. I ended up getting a y sustain board repaired by Coppell TV repair, and I installed it last night. The TV ran great, perfect picture. Today I start it up and I get what is in the attachments below. My stupid camera wouldn't focus very well, but I get like a 'rainbow' on both sides of the screen. It is most obvious when the picture is dark, or on startup. When there is a full scene on the screen it is just green sparkles.

Any ideas?

[PlainBill]

Re: HP PL4260N Damaged Y-Sustain

I'm back, with a new problem. I ended up getting a y sustain board repaired by Coppell TV repair, and I installed it last night. The TV ran great, perfect picture. Today I start it up and I get what is in the attachments below. My stupid camera wouldn't focus very well, but I get like a 'rainbow' on both sides of the screen. It is most obvious when the picture is dark, or on startup. When there is a full scene on the screen it is just green sparkles.

Any ideas?

Download the LG Plasma Quick Reference Alignment handbook from Elektrotanya and run through the setup procedure for this panel. A couple of settings require an oscilloscope. Tom66 has described a process for tweaking the pots to optimize those settings. It MAY be necessary to update the firmware on the main logic card; someone here has the jig to do that.

PlainBill

[rpgruss]

Re: HP PL4260N Damaged Y-Sustain

I have the service manual, so I can check out the settings. I don't have a scope so I'm kinda limited on that front, but I can definitely check the board voltages. I did check Vs and Va which are generated on the power supply, and they are dead on with the panel sticker.

One question: could it be a botched repair? Like I said, it ran fine the first time I turned it on, but then the 2nd time the problems started.

[PlainBill]

Re: HP PL4260N Damaged Y-Sustain

I have the service manual, so I can check out the settings. I don't have a scope so I'm kinda limited on that front, but I can definitely check the board voltages. I did check Vs and Va which are generated on the power supply, and they are dead on with the panel sticker.

One question: could it be a botched repair? Like I said, it ran fine the first time I turned it on, but then the 2nd time the problems started.

It could be, but it sounds more like an adjustment problem.

PlainBill