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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
LG led with black screen

 

 


sprinklerman
New User

Feb 26, 2018, 8:52 PM

Post #1 of 18 (941 views)
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LG led with black screen Can't Post

My 55" LG led tv, model #55LW5600, screen faded to black right in front of my eyes. I purchased a T CON board thinking that was a cheap easy fix. It didn't work. Please help me before I take it out back and fill it with 9mm holes. Thanks in advance.



jts1957
Veteran


Feb 26, 2018, 11:07 PM

Post #2 of 18 (930 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Careful, they've been known to return fire. Smile


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Location: Far, Far Away


Ballboy1066
New User

Feb 27, 2018, 2:13 PM

Post #3 of 18 (918 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Hi,

Firstly, I'm not an expert in TV repairs but, I have a lot of experience in other spheres to do with communications. There is wealth of information at your finger-tips nowadays on the I-Net.

I personally would not buy anything at the stage you're at until you've established what was causing the issue i.e. black screen. It might well have been the T-Con board but, you need to establish that with the 'Flashlight test' -see 'ShopJimmy' YouTube post-.

Now you're in a situation whereby the old T-Con, and the new for that matter, needs to be tested in the TV to see they produce an image on your black screen. If the old one is okay fine.. test the new one too.. if that's fine you could always sell it and recoup some cash to finance the real issue?

Have a look at the 'Youtube' posts -below- (there's lots more but, for my issues -similar to yours- I found them amongst the best; the technician's in them have different methods but are sound -IMHO-). I would do this research even before touching the TV.. you may need to buy/borrow/beg some test-meters.. In any event (and above all).. you need to adhere to health and safety. I apologise if I appear to be preaching but I hold your best interests at heart.

https://www.youtube.com/watch?v=2pyuXwNkBMA

https://www.youtube.com/watch?v=Bf5T2wwtydY&t=217s

I think it's worth persevering with.. you may end up with your TV back and not in the dumpster...
Hope this helps.. good luck.


sprinklerman
New User

Feb 27, 2018, 2:40 PM

Post #4 of 18 (912 views)
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Re: [Ballboy1066] LG led with black screen [In reply to] Can't Post

Thanks for the advice.
I have watched several videos and tried different test.
I will surely try these when i get home.
Notice the web address below.
Check out the test on page 58-59. Apparently the SMPS and Inverter are OK because the back light came on during test. I should mention that the back light will not come on by itself. Also the flash light test didn't work with either T-CON board.

Thanks again for the help! I refuse to give up on this thing.


http://pages.sssnet.com/test/LG_55LW5600_Training.pdf


jts1957
Veteran


Feb 27, 2018, 8:46 PM

Post #5 of 18 (909 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

With everything back to how it was when you first removed set back, What are PWR-ON & DRV-ON pins of P201 doing when you try to power up TV? Is relay engaging?


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Location: Far, Far Away


sprinklerman
New User

Feb 28, 2018, 1:21 AM

Post #6 of 18 (899 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

Yes I can hear the click. When AC power is removed I can also hear the click after the capiciters power down.


jts1957
Veteran


Feb 28, 2018, 1:54 AM

Post #7 of 18 (896 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

What are PWR-ON & DRV-ON pins of P201 doing when you try to power up TV?


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Location: Far, Far Away


sprinklerman
New User

Feb 28, 2018, 2:08 AM

Post #8 of 18 (892 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

Youíll have to excuse my ignorance. When I pull the P201 plug from the SMPS board to test those pins I get nothing. Nothing from any of the pins on that plug. Same for if I pull the P502 plug from the main board. Relay does however click on when I plug back in.


jts1957
Veteran


Feb 28, 2018, 2:21 AM

Post #9 of 18 (892 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post


Quote
With everything back to how it was when you first removed TV set back, What are PWR-ON & DRV-ON pins of P201 doing when you try to power up TV? Is relay engaging?


Who asked you to unplug some thing?
I asked what those two pins of P201 and relay were doing.


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Location: Far, Far Away


sprinklerman
New User

Feb 28, 2018, 2:29 AM

Post #10 of 18 (887 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

I didnít know how to get to the 24 pins with out doing so. There are only 12 legs I can test on P201. The PWR-ON is getting 3.2 volts while the 4th leg from the top (17 or 18) is getting 11.9.

Sorry Iím a pipe fitter by trade so excuse my lack of terminologies.


jts1957
Veteran


Feb 28, 2018, 2:47 AM

Post #11 of 18 (886 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Back probe the connector from the wire side. Pg 58 for P201 pinout. Board itself, Top & Bottom, are also labeled.


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Location: Far, Far Away

(This post was edited by jts1957 on Feb 28, 2018, 3:00 AM)


sprinklerman
New User

Feb 28, 2018, 3:23 AM

Post #12 of 18 (879 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

PWR-ON is at 3.2 and DRV-ON is 0.


jts1957
Veteran


Feb 28, 2018, 11:54 PM

Post #13 of 18 (870 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Jumpering DRV_ON to 3.2V does NOT cause BL to turn on when set is turned on? & BL does NOT come on when either P202 or P203 is disconnected? IF NO to these, plug all back in & remove jumpers then set a hair dryer on highest setting and heat components on the Main board (microprocessor & big heat sink especially) for about 5 minutes then try to turn TV on. IF BL come on when hot, Bad Main board.


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Location: Far, Far Away


sprinklerman
New User

Mar 1, 2018, 1:38 AM

Post #14 of 18 (865 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

Jumpering DRV ON to 3.2v DOES turn on the BL. BL does NOT come on when either P202 or P203 is disconnected.

Should i still try th hair dryer?

The colors got distorted and then faded to black in a matter of fifteen minutes. Does this sound like a main board going bad?

Thanks


jts1957
Veteran


Mar 1, 2018, 2:28 AM

Post #15 of 18 (863 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Try it. I've seen others with that solution.


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Location: Far, Far Away


sprinklerman
New User

Mar 2, 2018, 2:46 AM

Post #16 of 18 (862 views)
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Re: [jts1957] LG led with black screen [In reply to] Can't Post

It didnít work


sprinklerman
New User

Mar 3, 2018, 2:10 PM

Post #17 of 18 (852 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Any other ideas? Iím starting to think it has to be the main board. The new T CON board didnít work. When i did the jumper test the LEDS came on. What else could it be?


jts1957
Veteran


Mar 3, 2018, 7:03 PM

Post #18 of 18 (847 views)
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Re: [sprinklerman] LG led with black screen [In reply to] Can't Post

Main boards are cheaper than panels.


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Location: Far, Far Away

 
 
 


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