LG 50PG20-UA No picture, good sound.

[crashomatic]

I have a LG 50PG20-UA and I have no picture, sound is fine. Visual inspection shows no sign of trouble on the boards. If I remove the upper y-buff and I get the bottom half of the screen to go white, bright for a few seconds, then about half as bright. Upper y-buff back in and the screen gets nothing. Is this most likely a bad upper y-buff and is it worth ordering that card to see if it fixes it?

Thanks

[tom66]

Re: LG 50PG20-UA No picture, good sound.

Can you post pictures of the boards in your set?
On the control board, do you see a blinking LED?

[crashomatic]

Re: LG 50PG20-UA No picture, good sound.

There is one solid light (the middle one) on the main control board when you turn the television on. When power is applied, the power switch turns blue, then immediately red. When the button is pressed, it flashes blue three times and stays solid on the last time.

[crashomatic]

Re: LG 50PG20-UA No picture, good sound.

Anybody have any Ideas?

[CoppellTVRepair]

Re: LG 50PG20-UA No picture, good sound.

The last LG 50PG20 we serviced in the shop had a single upper buffer failure.

Chances are this is what you have too and chances are it may have affected the lower buffer and/or the sustain board.

But in my opinion this is less likely.

When I find time I'll post a quick review at our blog on how to test the buffer with a meter.

Basically it's very similar to the way buffers are tested in

http://blog.coppelltvrepair.com/2010...-lines-in.html

and

http://blog.coppelltvrepair.com/2010...er-boards.html

All plasma buffer boards have 3 rails of particular interest: one is ground (also known as "floating ground" and diferrent from the grounded chassis; this is ground only for the output plasma buffer) and two voltage supplies: low voltage logic supply which is almost always +5V and the high voltage sustain output, which varies, but say it goes as high as north of 200V.

One must find the ground, the data voltage and the sustain output on a buffer board and test for short on them; most commonly the short is between the sustain output and ground, but it can also be in the data logic.
Also it does not necessarily need to be exactly short - any low resistance which is very close or similar in both directions is indicative of a problem.

It is 11 PM and I am in bed now, responding to a customer direct email asking to review the post here, so I do not have a buffer board and can't tell which are the pins tha need to be tested there.

But the ground is usually the most widespread pin on the connector and the other two almost always have at least two connectrs dedicated to them.

There are exceptions to the above, of course, but I've tested those particular buffer boards and they weren't anything unusual.

We (Coppell TV Repair) carry both the upper and the lower buffers at our store.

Find them through http://www.coppelltvrepair.com/search .


Hope this helps!

[crashomatic]

Re: LG 50PG20-UA No picture, good sound.

Helps tremendously! Thanks!

[crashomatic]

Re: LG 50PG20-UA No picture, good sound.

Fixed. I was distracted for a while by the birth of my daughter, but back to the thread.

The replacement of the upper y-buff fixed the issue.

Thanks for the help CoppellTVRepair !!!
https://www.badcaps.net/forum/member.php?u=29386

[mmartell]

Re: LG 50PG20-UA No picture, good sound.

Congratulations ! On both !!!

[efan]

Re: LG 50PG20-UA No picture, good sound.

Same problem here. The part number for it is EBR50039003. However there is not this part on ebay. I wonder if EBR50039001 can be used as an alternative. Thanks.

[tw2005]

Re: LG 50PG20-UA No picture, good sound.

Shopjimmy has them as compatible. http://www.shopjimmy.com/lg-ebr50039...scan-drive.htm

[efan]

Re: LG 50PG20-UA No picture, good sound.

Thanks. www.partstore.com has it in stock. However, it cannot be ordered in canada.
https://www.partstore.com/Part/LG+El...39003/New.aspx

[efan]

Re: LG 50PG20-UA No picture, good sound.

Ordered EBR50039003 from partstore.com. It comes EBR50039001, anyway, the TV works.