LG LN530B-UA No Backlights Black Screen


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LG LN530B-UA No Backlights Black Screen

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Barry19115
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Dec 1, 2015, 2:20 PM

Post #1 of 16 (4475 views)
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LG LN530B-UA No Backlights Black Screen	Can't Post

I have an LG LN530B-UA TV. This is a 32" LED TV. I bought the TV in January of 2014, so it is not even 2 years old. I am NOT a TV tech. I am a computer tech, tho..

I DO have audio and I DO see images with the "flashlight" test. The standby light does go off when the TV is turned on.

The TV seemed to be fine one minute then I left the room and when I came back, all I had was a BLACK screen. I see NO lights inside when I remove the cover.

I have gone through the videos from SJ and determined that the "most likely" cause was the Power Supply board. I ordered and received the Power Supply from SJ and it DID NOT make any difference at all. Actually the Power Supply they sent me is 1 year older than the one I have in the set. It is also a different Rev. The PS I have in my set is Rev.3 and the one they sent me is Rev. 1.

I could order a replacement from SJ or I can get a Main Board on ebay somewhere..there are few "new" Main boards listed..

Any recommendations and all help will be very much appreciated

jts1957
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Dec 1, 2015, 8:45 PM

Post #2 of 16 (4468 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

I presume you just ignore those pesky numerals before the 'LN'?

You don't mention any 'flash/logo' when first plugged in /powered on.

PS would be "most likely" cause for CCFL back lighted panels, yours is LED.

OR you could open the panel to be sure each and EVERY LED lights.

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Location: Far, Far Away

Barry19115
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Dec 1, 2015, 9:02 PM

Post #3 of 16 (4464 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Thanks for getting back to me jts1957,

Yep..just forgot the "32" in front..which makes it 32ln530b-ua.. I get absolutely NOTHING when the TV goes on. I used to get the channel identifier in the upper left hand corner when the set turned on..I don't even get that any more..

I am going to have to take a look and see how much trouble it is to open the panel. I don't even see any LED strips for sale, even on eBay..not 32 inch, anyway.

I did order a Main board on eBay to try out. It is supposedly "new". If that don't work, the next step would be to open the panel. SJ shows an IC as a repair part, but there is no way that I can solder that tiny thing.

One thing is for sure..eventually parts are gonna fail. That's the way they are built. I have not had this set for even 2 years yet..

jts1957
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Dec 1, 2015, 9:51 PM

Post #4 of 16 (4458 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

LEDs at the 100% defaults, cause the picture looks the best, will do that.

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Location: Far, Far Away

Barry19115
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Dec 1, 2015, 9:59 PM

Post #5 of 16 (4456 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Jts1957,

I don't know if I have it cranked up all the way to full brightness.. I doubt it, .. I can't tell since it will not go on.

How can one tell if it's the LED's or the power board or the main board..that is my dilemma..there are no lights lit that I can see at all inside even with the back off.. Do LED's fail in less than 2 years?

jts1957
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Dec 1, 2015, 10:26 PM

Post #6 of 16 (4454 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

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LEDs at the 100% defaults

You would first have to recall having to decrease them back when the set was NEW. It is a manufacturers DEFAULT setting - Every set being boxed and shipped is at that setting.

Quote

I DO have audio and I DO see images with the "flashlight" test. The standby light does go off when the TV is turned on.

One can presume that with two separate PS boards, that at least one would be outputting DC voltage to one (or more) LED strings.

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Do LED's fail in less than 2 years?

YES! Go back in time and ask the developers of the first electric Christmas tree light strings.

Most light emitting diodes can be checked by putting approximately 3 Volts across EACH LED, one at a time, observing polarity, or by putting the approximate correct total DC voltage on each string. Of course, in each case, the DC supplies' current capability must equal or exceed the expected demand.

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Location: Far, Far Away

Barry19115
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Dec 1, 2015, 10:38 PM

Post #7 of 16 (4452 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Once again.. I have NO lights lit.. at least that I can see with the back off.

Do you know if they are wired in series or parallel like Christmas lights..that is if one goes out, they all go out..?

If LED's are out, where do I even get replacements for them??? In order to test them l I would have to build something that would allow me to apply about 3 volts to each one. I do have multi-meters, but they don't output any voltage at all..

jts1957
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Dec 1, 2015, 11:06 PM

Post #8 of 16 (4450 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

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Go back in time and ask the developers of the first electric Christmas tree light strings

Elaborating on the above: The developers took their old fashioned light emitting incandescent lamp bulbs, and realizing that a particular number of the bulbs they were using, when wired IN SERIES would conveniently use most of the 120VAC line voltage that they were plugging them into. I'm absolutely positive they had a smirk on their face as they knew the troubleshooting hassles this approach would cause.

You don't have TWO 1.2V to 1.5V Coin-type on up to flashlight size 'D' batteries that you can wire in series?

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If LED's are out, where do I even get replacements for them???

If only one, I've seen people bypass the bad one; a junk set; Digikey, Mouser. Just have to match ratings, including light temperature - nothing worse than having a single LED that's 'bluer' or 'yellower' than rest. Sometimes a 'Used' one more closely matches (including hours of usage on LED).

I thought you claimed to be a computer tech?

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Location: Far, Far Away

Barry19115
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Dec 1, 2015, 11:39 PM

Post #9 of 16 (4448 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

I didn't say I didn't have them..what I said is that I need to BUILD something that would output 3 volts.. I would want something stable that I could use more than once..

I have tons of batteries and I do buy my stuff from Digikey and Mouser, but I have never had a TV to deal with. I have repaired monitors with parts from Mouser..mostly bad capacitors..

I have only been in the computer field for the last 48 years and I guess I'm still a novice..

I guess we will find out if the problem is the Main board or not when I get it..until then, I am not going to tear the TV down to the LED level to test them.. It could very well be the IC, too..

jts1957
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Dec 1, 2015, 11:57 PM

Post #10 of 16 (4447 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

IC1300 EEPROM. By all means try that first. Board or IC, just be sure all info matches.

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Location: Far, Far Away

Barry19115
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Dec 2, 2015, 1:13 PM

Post #11 of 16 (4438 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

I opted to change the board. IC1300 is way too tiny for me to even attempt to change.

It's only a few mm square with 8 solder posts. I would ruin the entire board if I even tried to remove the IC and put a new one in.

I have a new board on the way and it was hard to even find that. I needed the board number (the number on the sticker) and MFG. part number to be exactly the same..

Barry19115
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Dec 8, 2015, 6:56 PM

Post #12 of 16 (4408 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Does anybody out there know where to by LG LED backlight strips for an LG 32LN530B-UA with a Panel Number HC320DXN-ABFPI-21XX.??

I have tried a new power supply, but that is not the problem. When I check the voltage at the power supply, it is HIGH which leads me to believe that it's a problem wit the LED's themselves. I would replace ALL of them, not just one or two.. I think three are 3 strips involved..

jts1957
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Dec 9, 2015, 12:24 AM

Post #13 of 16 (4400 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Power Supply ... check
Main board (IC1300) ... ?
Visual confirmation of one (or more) LEDs failing to illuminate ... ?

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Location: Far, Far Away

Barry19115
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Dec 9, 2015, 1:13 PM

Post #14 of 16 (4391 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

Thanks jts.. I ordered a new main board, but it came DOA. I am now waiting for a reply from the vendor..so far it's been 3 days and I have not heard a word back as to whether they are gonna send a new board, return this one or whatever..can't order another till I hear something.I don't have deep pockets or I would not be going thru this exercise at all ..

In the meantime I came across this SJ youtube video. https://www.youtube.com/watch?v=2pyuXwNkBMA At about the 4 minute mark you will see what I see on my TV. Scenario 2, I think. My Voltages are fluctuating between around 125 and 132 volts on the meter. Keep in mind, I'm NOT a TV tech..

Now, if I can't locate a source for the LED strips, I am not going to tear the unit down in order to get to the LED's to test or see them individually. I would only replace the full set, not individual LED's

jts1957
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Dec 9, 2015, 3:01 PM

Post #15 of 16 (4389 views)
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Re: [Barry19115] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

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Scenario 2, I think. My Voltages are fluctuating between around 125 and 132 volts on the meter. Keep in mind, I'm NOT a TV tech..

1) Wrong TV Models being compared;
2) Wrong Panel type number being compared;
3) As Power Supply part number was never actually specified in your thread, I can't say whether it matches or not (search based on full model number which you finally provided does indicate it being used for that model).

As long as you're extrapolating this far, why not go with same strips they were using (for the TV model numbers they found them for - of coarse SJ will No longer have any available. Since SJ strips down TVs to obtain some of their parts, I see nothing in their pages that say anything about LED strips having been New or Used.)

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(This post was edited by jts1957 on Dec 9, 2015, 3:14 PM)

Barry19115
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Dec 9, 2015, 3:18 PM

Post #16 of 16 (4384 views)
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Re: [jts1957] LG LN530B-UA No Backlights Black Screen [In reply to]	Can't Post

I know it's not the same TV or model number, but it IS the same series of TV's and they should all work about the same as far as supplying power to the unit.

I just checked and both units use the SAME power supply. Mine AND the one in the video

SJ does not have the strips I need. I emailed them as well as checked the site.

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