Author Topic: LG LED TV repair attempt  (Read 1343 times)

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Offline protonq

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LG LED TV repair attempt
« on: October 03, 2018, 03:49:07 am »
Hi all. I'd like to request a little help if I may. I'm trying to repair an LG 60UF8500 LED TV. I've attached picture and video of the problem.
All the menu functions and audio work. Does this look like it could be the tcon, main board or a hopelessly broken panel?



I have tried re-seating the connectors.
Thanks so much for any help!
« Last Edit: October 03, 2018, 03:52:16 am by protonq »
 

Offline Rasz

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Re: LG LED TV repair attempt
« Reply #1 on: October 03, 2018, 04:19:26 am »
trash,  defect in glass or chip on flex buffers
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Offline Gyro

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Re: LG LED TV repair attempt
« Reply #2 on: October 03, 2018, 08:54:24 am »
No, I'm not so sure about that one, there are no fixed artifacts, just multiple moving un-synchronized image portions. I would go for mainboard or T-con in no particular order.

The first thing to check would be power supply rails, the usual bulged capacitors etc. It's quite possible for MLCC capacitors to fail on the T-con, messing up bias voltages etc. There are lots of local voltage regulators that could be in distress.
« Last Edit: October 03, 2018, 08:55:58 am by Gyro »
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Offline protonq

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Re: LG LED TV repair attempt
« Reply #3 on: October 03, 2018, 10:09:51 am »
 I was about to trash it but what you're saying makes sense.I'm going to try and find the service manual so I can hit it with the meter and check voltages.
I already ordered a tcon on Ebay which should come later today.

Thanks again both of you for your help.
 

Offline Rasz

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Re: LG LED TV repair attempt
« Reply #4 on: October 03, 2018, 10:54:52 am »
bias would be bad colors/filling with single color
flickering/scrolling means bad sync, deserializers on flex or connections in glass, there is a slight possibility its higher up the chain
4k 120 Hz means you can forget about universal scalers to check that assumption, Tcon will run you $50 for a blind shot
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My fireplace is on fire, but in all the wrong places.
 

Offline Shock

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Re: LG LED TV repair attempt
« Reply #5 on: October 03, 2018, 04:13:12 pm »
A slightly useful test is to try each side of the tcon output individually so see if you can get half the panel to come up good on one side. Do the disconnecting/connecting while the TV is not connected to power.
« Last Edit: October 03, 2018, 04:14:54 pm by Shock »
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline HpMad

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Re: LG LED TV repair attempt
« Reply #6 on: October 03, 2018, 09:50:10 pm »
First you must check the flex cables, and check if they are not oxidized or the video chip sometimes needs soldering. Buying a new T-com could solve the problem but you will spend 50 dollars that you could solve with a little tin.
« Last Edit: October 05, 2018, 06:31:46 am by HpMad »
 

Offline cvanc

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Re: LG LED TV repair attempt
« Reply #7 on: October 04, 2018, 12:41:28 am »
First you must check the flex cables, and check if they are not sulfated

Not to sidetrack, but I've not heard this term before.  Care to elaborate?  If you have this problem, what does it look like & what do you do about it?  Thanks.
 

Offline Shock

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Re: LG LED TV repair attempt
« Reply #8 on: October 04, 2018, 01:05:25 am »
First you must check the flex cables, and check if they are not sulfated

Not to sidetrack, but I've not heard this term before.  Care to elaborate?  If you have this problem, what does it look like & what do you do about it?  Thanks.

I think he means to say oxidized.
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 
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Offline HpMad

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Re: LG LED TV repair attempt
« Reply #9 on: October 05, 2018, 06:19:35 am »
Ok! english is not my first language is spanish in spanish we say "sulfated"  to mean "oxidized" in electronics, but i guess you caught the point     
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