LG 50PK750 plasma, repair tech gave up!

[sold2early]

The TV will not power up. The screen lights up for 1 second and then shuts off. The problem occurred about a week after a power outage; the TV was off at the time and was plugged into a surge protector. I believe the TV did work for a few days after that event.

The LG repair tech made 4 unsuccessful attempts to fix it (under warranty) and then said he could do nothing more. He replaced the power supply board as well as the entire panel and it is still doing the same thing.

The good news is that LG is giving me a new TV and I get to keep the old one. I'd like to fix it, but it seems like virtually all of the guts have been replaced! I haven't done any diagnostic work yet other than visually inspect the caps, which look OK.

Any ideas?

[graham01]

Re: LG 50PK750 plasma, repair tech gave up!

Hi there,

I am currently having an issue with my plasma TV, which I have been seeking help for on here also. It sounds similar to mine, bare in mind I do not know nothing about Plasmas! However I once had an LCD TV that was plugged in using a surge protector, and during a power surge it died. It turned out to be the mother board had blown, and the only reason I can think is that my freeview box sent a spike through the HDMI, blowing some very sensitive components.

It seems in your case that the PSU is okay. Plasmas do flash first when turned on initially, if that flash seems like its standard start up then it could be all your sustain boards are functioning correctly. Just do a few checks, although I do not know how relevant they really are..

Turn the TV on in a dark room and watch the screen carefully. Does it flash white initially, then remain black but SLIGHTLY illuminated for a few more seconds? You will not be able to notice the black illumination until it changes to completely off again, so try to pick up on it.

Do the TV buttons respond? If you try to power off the TV either with the TV buttons or the remote, will it actually turn off?

My plasma TV that i am currently having problems with; it turns on, flashes white once, then the screen is slightly illuminated for a few more seconds. Once the TV is on, the buttons on the front of the TV asre unresponsive. The LED on the front of the TV flashes as a response to remote functions only, but it will not actually respond.. As in, pressing the power button does not turn the TV off.. It turns out the main board is at fault, I managed to diagnose it using parts from another TV.

Regards

[randtek]

Re: LG 50PK750 plasma, repair tech gave up!

Logic would indicate that you hae a bad main board, unless you are not mentioning all parts that were replaced. LG Plasma panels come with all boards except the power and main boards. If the panel and power boards were both replaced, then the main board is pretty much the only thing left.

[cadiman]

Re: LG 50PK750 plasma, repair tech gave up!

There is a post here somewhere and I had one too. (faulty sound board)

I had a tv with a bad amplifier (sound) board and it would shut the power supply down which in turn would shut off the tv.

There is always a reason for a power supply to shut down.

Sometimes it`s the power supply

Sometimes it`s the boards it is trying to power up.

[Frankwhy]

Re: LG 50PK750 plasma, repair tech gave up!

My TV is 50PK750, behaves the same way as mentioned. While every one thinks it is a bad capacitor, I found out it was a bad resistor on the power board, I ordered one of the in kind from Digikey (part number A102460-ND) and the TV works again. I think it may help.

The resistor is a bulky white ceramic 5W 22 Omega, marked as 5WJ22Omega (Sorry I do not know how to type the Greek Omega), about one inch high, half inch wide, quarter inch thick. It is located on the right upper conner of the power board if you look it from behind the TV, usually two of them lined up together. One of them on my board is open. While it was still on the board, the resistance measurement is fairly stange, the resistance is a keep increasing one, couple of hundreds of K omega to start with, and increasing all the time during my measurement, probably I was measureing the other non-open circuit with some capacitors (The good one measures 22 omega).

The picture of the resistor on power board is bellow, not sure if I can make it work

http://www.flickr.com/photos/25691848@N04/7973585186/

[EvilGhozt]

Re: LG 50PK750 plasma, repair tech gave up!

as mentioned earlier. Check the effect resistors at power board. I once got a similar LG tv with broken 5w resistor...

[BuGG]

Re: LG 50PK750 plasma, repair tech gave up!

Worked great, thanks!

[chevy56]

Re: LG 50PK750 plasma, repair tech gave up!

I put in the replacement kit for this model and didn't help.The led is flashing on the control board does this mean the control board is bad?

[tom66]

Re: LG 50PK750 plasma, repair tech gave up!

Flashing LED indicates working control board

[chevy56]

Re: LG 50PK750 plasma, repair tech gave up!

The TV will not power up. The screen lights up for 1 second and then shuts off. The problem occurred about a week after a power outage; the TV was off at the time and was plugged into a surge protector. I believe the TV did work for a few days after that event.

The LG repair tech made 4 unsuccessful attempts to fix it (under warranty) and then said he could do nothing more. He replaced the power supply board as well as the entire panel and it is still doing the same thing.

The good news is that LG is giving me a new TV and I get to keep the old one. I'd like to fix it, but it seems like virtually all of the guts have been replaced! I haven't done any diagnostic work yet other than visually inspect the caps, which look OK.

Any ideas?

I fixed mine by finding one leg of D70 with no solder,resoldered it works fine.I needed the repair kit also one resistor was open so I put everything in the kit in.After all that it needed resoldered to work

[Brentsky]

Re: LG 50PK750 plasma, repair tech gave up!

Hello all, I have a LG/Zenith Z50PJ240 model TV and when plugged in I get a red led then it tries to power on and clicks once and the led go's out then it tries again and clicks and the led comes back on. after ggogling I came across mention of it being a common problem in a few LG sets with EAY60968701 power supply boards and ordered a repair kit and installed it all. I got the same results after rebuilding it so I ordered a new power supply board from a reliable source and I get the same result. Can anyone pint me in the direction of what to do to troubleshoot this tv. when it clicks on or tries I get no flashes from the screen but the optical audio lights up until it clicks back of in a couple seconds like 2-3... i have tried disconnecting each and all boards as well as the touch panel button connector on the IR remote/power button board and with them each disconnected 1 by 1 (other than the main which is needed to turn it on of course) My guess would be that it has to be the main board being that it doesn't even seem to attempt to fire the screen at all but I'm by no means a TV tech. Can anyone point me the right way here. I don't have new thread posting privileges or I would start a thread for it. thanks..