LED tests good,controller good and all boards replaced

Rebelwoc

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Apr 5, 2017
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Working on a LG32LN630 B-UA. The people I got it from said they replaced the T-Con board and had no luck. It was cost effective for me just to get a repair kit with all boards and replace them all. Still no picture but the flashlight test shows a picture. Unplugged the LED array and powered it up with my tester and it works. I powered up the TV's boards with the LEDs powered separately by the tester and I have a picture. When the LEDs are plugged back into the controller and the set is powered on, no picture again. Besides cables, which looked good, any ideas?
 

maxwellmelon

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Oct 2, 2013
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On your power board the top white connector what is the voltage reading do you get from pin 1 to pin4 (the very left and right pin) the left pin is + the right will be -.....be careful as you read it not to short it out. you will need to do this while tv is powered on. Take care as the rest of that board has extremely high voltages only take the voltage at the connector.

This is the power to your led.

bad T-con boards do this and have nothing do with the backlight but the screen image

https://www.bing.com/images/search?view=detailV2&ccid=dxGTlQaG&id=D370968611FBF3E5DCE2D4A17E82046449251742&q=bad+t-con+board&simid=608049473696631752&selectedIndex=12&ajaxhist=0

https://www.bing.com/images/search?view=detailV2&ccid=LJrKNuwJ&id=D103044CFF5919A97C43B2E053DA647AE455340B&q=bad+t-con+board&simid=608003989987001740&selectedIndex=0&ajaxhist=0

https://www.bing.com/images/search?view=detailV2&ccid=TJI7idz4&id=087EDADE69844FFFCB41C0F55BDCDAB5EAAB91A9&q=bad+t-con+board&simid=608036288141263090&selectedIndex=11&ajaxhist=0

I'm really guessing that power board is not providing power to the led as it should or not receiving the POB (power on backlight) signal on the wire from the main processing board.
 

maxwellmelon

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have you checked the polarity of the led power on the main board plug? does the positive and negative match the post and negative correctly on the led cable?

The tcon board has nothing to do with the backlights. the backlights will light up even with no tcon board installed.

Just as a question on this model does your led plug into the voltage board or the main board?

if it plugs into the main board I would say its a bad main board. if it plugs into the power board it can be a bad power board or a bad communication wire between the main board to the power board. then again you might not even have a power board if this tv uses a power brick which means something is incorrect with the main board.

ive repaired quite a few tvs so ill try to help you. some pictures of the boards might be helpful but I cant say for sure
 

Rebelwoc

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Apr 5, 2017
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Hey Max,
This unit had the symptoms of t-con board. Picture out with audio and all other functions working. I just fixed a 60 " and a 32" Vizio with the same exact problem. For this LG because the previous owners had said they had replaced the t-con already I just ordered a repair kit from ShopJimmy with all of the boards and cables. It was cheaper and all inclusive, not very smart now that I am in this situation.
I have an LED tester I just got that will test the LED's without disassembly by powering them up. They do power up and if you leave the LED's unplugged while powering up the TV you actually get a picture which means the power supply board is good. I checked all cables last night and had a new one the goes to the power supply board from the main board so I put it in just for G.P.. Nothing has changed. Checked all connections and plugs it has me a bit perplexed.
 

maxwellmelon

Honorable
Oct 2, 2013
171
0
10,910
52
On your power board the top white connector what is the voltage reading do you get from pin 1 to pin4 (the very left and right pin) the left pin is + the right will be -.....be careful as you read it not to short it out. you will need to do this while tv is powered on. Take care as the rest of that board has extremely high voltages only take the voltage at the connector.

This is the power to your led.

bad T-con boards do this and have nothing do with the backlight but the screen image

https://www.bing.com/images/search?view=detailV2&ccid=dxGTlQaG&id=D370968611FBF3E5DCE2D4A17E82046449251742&q=bad+t-con+board&simid=608049473696631752&selectedIndex=12&ajaxhist=0

https://www.bing.com/images/search?view=detailV2&ccid=LJrKNuwJ&id=D103044CFF5919A97C43B2E053DA647AE455340B&q=bad+t-con+board&simid=608003989987001740&selectedIndex=0&ajaxhist=0

https://www.bing.com/images/search?view=detailV2&ccid=TJI7idz4&id=087EDADE69844FFFCB41C0F55BDCDAB5EAAB91A9&q=bad+t-con+board&simid=608036288141263090&selectedIndex=11&ajaxhist=0

I'm really guessing that power board is not providing power to the led as it should or not receiving the POB (power on backlight) signal on the wire from the main processing board.
 
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