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Russell H.
Russell H., Service Tech
Category: TV
Satisfied Customers: 11195
Experience:  8+ years of professional experience
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This is ***** *****. Fixing a 50PG20. Followed one of your

Customer Question

Customer: This is ***** *****. Fixing a 50PG20. Followed one of your threads. Measured VS and VA OK. Sinks on y board and Z board both cold. Disconnected upper y buffer and screen all black. This is where my results diverge from the thread so need your help.
JA: Thanks. Can you give me any more details about your issue?
Customer: Screen black. not sure if i have sound, could hook up to cable and test for sound if that helps.
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to TV Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: no problem, worth every penny.
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: TV
Expert:  Russell H. replied 1 year ago.

Hi, thank you for contacting My name is Russell. I will do my best to provide the right answer to your question. It seemed right to offer my help, since Expert Nolan has not picked up on this case in some time, despite the case being marked for his attention.

What other symptoms does the TV have? even Expert Nolan might have to ask this, since you assume a knowledge and recognition of the other case, that nobody may have here anymore, since we serve many customers per day almost every day or every day.

I assume it lacks a screen image, and also has a 'flash code' showing on the Power light or other light visible without removing the outer case.

This usually means a shorted component inside the TV, but cases always differ.

Please determine whether the TV is producing / tuning in any sound at all. That is important as details and symptoms go.

I suspect that you could use the guidance of a service manual for your model of LG PG20 TV.

Here is a free source for one, oddly titled 'Training Manual' but apparently having to do with the diagnosis and troubleshooting of this model line:

- note: load this page, then wait 30 seconds or more. It takes time for the actual link to the download to properly appear.

After that interval, scroll down, avoiding all the big banners that say 'Download', none of which are essential, to below the Preview image of the first page, and look for a link that says

Get Manual

and click on that link and nothing else, to download the manual. That link does not appear at first, so you have to wait a bit for it.

There are other sources for service manuals for this model line... please tell me more about the symptoms the TV is showing, how it is behaving, so that we may advise you more specifically and from a standpoint of knowing as much as you do (at least.) Thanks.

Customer: replied 1 year ago.
I have the manual but it is not as good as instructions on your site like "Measure VS & VA and if good are the heat sinks on Y board &Z board both cold?" Hooked cable up to get sound but not sure if I was on the right input since no display when i run through inputs using the input button. I think there is no sound. Power light appears normal red and then turns to blue when you press it, not a flash code that means something. I used the manual to get to the measure VS & VA but the manual doesn't steer me past that.-----Mike
Expert:  Russell H. replied 1 year ago.

No picture, no sound... this makes me ask what may sound a little odd as questions go: Do you have any input to the TV?

Of course, if nothing comes up even when you press MENU (there should be a MENU button on the TV), then the screen is not working.

If the heat sinks are *cold* despite voltages from supply being good, even after 1 hour's operation, then the boards the cold heat sinks are on have not switched On or are otherwise not operational. No flash code... but other signs of something very wrong with the TV such as no picture... means the logic board or 'main board', the one with most of the chips/integrated circuit packages on it, is suspect, I think. That goes with the Y and Z boards not being 'turned On' if they have persistently cold heat sinks, since the logic board controls whether the other parts of the TV are 'On', speaking loosely and as far as my knowledge goes.

But you might want another Expert's opinion on this, since I think your TV model is a plasma type, and I'm not as good at plasma TVs as I might be. Let me know what you think. Thanks.

Customer: replied 1 year ago.
I need guidance to the next step. What should i test nex?. In the thread I was using, the next step which is disconnect upper y board and look at screen and tell me what you see. I need that kind of guidance and am willing to wait for it. Appreciate you stepping in, but let's wait for the expert to tell me the next step.---------Mike
Expert:  Russell H. replied 1 year ago.

OK, then, I have Opted Out of this case, leaving it on the note that though I'm not at my best on plasma TVs, I suspect that the Main Logic board in this TV may be defective.

Customer: replied 1 year ago.
There is probably some simple test to confirm your theory. That's what we need. Thanks for trying.
Expert:  Russell H. replied 1 year ago.

I honestly don't know that these video tutorials are reliable in detail, but you haven't been taken up by any other Expert, so I have to mention these videos:


Note that these videos are not supposed to substitute for a good plasma TV Expert's advice here at JustAnswer. They are simply my acknowledgment that we know you're waiting for such an Expert, and I care about your need for a plasma TV Expert.

Customer: replied 1 year ago.
appreciate these videos. any idea when expert will get back to me?
Expert:  Russell H. replied 1 year ago.

any idea when expert will get back to me?

I have no control over when an Expert on Plasma TV problems will take up this case, unfortunately. I've done what I could for the case, and have Opted Out. (Remember, it is the Christmas season, and many may be taking time off from work... which is how I would venture to explain the lack of response as yet.)