Author Topic: LG TV: image = No. sound = Yes  (Read 1905 times)

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downunder

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Re: LG TV: image = No. sound = Yes
« Reply #15 on: November 29, 2021,18:40:45 »

Those are the boards. The circled part is just a piece of fancy foam to prevent the board touching the metal strip. There are quite a few capacitors on each board, each soldered to the board at both ends. .These are the cap. terminals across which you need to measure. The gold spots are likely test points but I have no idea what they're used for. I see you have a digital meter so use ohms or the beep function. A reading below 100 ohms is suspect. If you find any, reverse the meter probes and recheck. It may read OK the other way. You'll likely find a matching cap on the other boards so you may compare reading. A totally shorted one would be a bonus as it will probably be your offender.

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Re: LG TV: image = No. sound = Yes
« Reply #15 on: November 29, 2021,18:40:45 »

Snuf3

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Re: LG TV: image = No. sound = Yes
« Reply #16 on: December 23, 2021,08:36:42 »
Hi Bruce
How are you?
I checked the capacitors and they seems fine.
I took a bit of alcohol and I washed off the blue marker that was on the red cable(It came like that from the factory). It had an impact. By doing so and by blocking some stripes with a tape, the red cable show strong white input {{see image attached}}.
stronger than the white cable which give a weak and fade signal. By connecting the red and the white cables I managed to see a bright full screen.
Another thing that I think may help. There is a buzz sound from the motherboard. It continue also after turning off the TV. it dies only by taking the power cable out of the socket.

 I feel like advancing. I finally got the red cable to show life signals and I found out about the noise.
it comes exactly behind the metal bar the I guess hide the integrated t-con.

Do you have a guess?
« Last Edit: December 23, 2021,08:40:26 by Snuf3 »

downunder

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Re: LG TV: image = No. sound = Yes
« Reply #17 on: December 24, 2021,03:03:27 »

Are you saying the buzz is coming from the Main board (the one with all the AV inputs on it)? And have you noticed the buzz before? I can only suggest that perhaps by blocking some stripes it has somehow upset the T-con on the main board. Is the buzz affected by finger pressure?

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Re: LG TV: image = No. sound = Yes
« Reply #17 on: December 24, 2021,03:03:27 »

Snuf3

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Re: LG TV: image = No. sound = Yes
« Reply #18 on: December 25, 2021,07:15:40 »
Yes the buzz is coming from the main board. I haven't noticed the buzz before but it may be due to the fact that I didn't listened to noises . I think that I tried to press the metal cover of the T con and nothing happened. I would love to uncover that T con but the it's a bit tricky. there are 2 plastic screws with a Spring mechanism well I have a tendency to break things when I don't understand how they work so maybe I will save it for later
there is also a strange behavior: when I turn on the tv I see:

first I see only the left side which is really dim.
After 20 second a stripe appear on the right side
then the left side become bright almost perfect white!
and after that the right side become bright but more gray in color

there is a timing notion. I imagine it because of the blocked stripes on the cable
this is a 10 seconds video I made that describe 1 min of reality
I speed it up so it won't be boring to watch
https://youtu.be/6OuithZyBNg

would you  say that the fact that I advanced from no image to very bright image is improvement? or am I at the same stating point?
« Last Edit: December 25, 2021,09:02:36 by Snuf3 »

downunder

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Re: LG TV: image = No. sound = Yes
« Reply #19 on: December 25, 2021,20:45:54 »

Well, it's  an improvement of sorts. So the metal cover I suspect is the heat sink for the microprocessor. The plastic "screws" are usually press-in from the top side.
On the reverse side you'll see a bulge in the plastic pin which you squeeze with long-nose pliers and work the pin out. Doubt if you need to do that though as all you'll mostly see is the top of the microprocessor. Does that metal cover get super-hot to touch and have you ever had an actual picture on the screen in its current state. Have you tried heating the main board in a household oven for 10 min. @ 180 deg. This used to recover LG main boards -albeit temporarily - but it doesn't seem to work on more recent LG tvs. Watched the video and my conclusion is main board or panel faulty, most likely panel if taping has resulted in some change to the display - not the Christmas joy you wanted.

Snuf3

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Re: LG TV: image = No. sound = Yes
« Reply #20 on: January 18, 2022,05:49:49 »
Hi Bruce
I wanted to thank you a lot for the time, the energy, and for being next to me in this journey of trying to fix a TV with no skills/tools on my part.
I kept a Beer in my fridge for 2 months and I said that I will open it when I will have a new TV
I don't have a new TV but I opened the beer yesterday since I manage to fix my broken TV. I am sure that without your advice and help I would have given up a long time ago.
the fix was:  blocking 2 stripes on the Red cable after a lot of trying an error to find out which is the faulty stripe.
Thanks again, pal. I am proud of myself and also proud that there are good people like you.
Have a nice year
Hug.
« Last Edit: January 18, 2022,05:54:11 by Snuf3 »

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Re: LG TV: image = No. sound = Yes
« Reply #20 on: January 18, 2022,05:49:49 »

downunder

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Re: LG TV: image = No. sound = Yes
« Reply #21 on: January 19, 2022,02:15:58 »

Glad my input was of help. Nothing wrong with that picture. Now it's beer o'clock but it looks like you've been at it already - that bottle looks like its been cracked open. Blocking LVDS strips is a somewhat arduous task. If I find it soon enough, then its too bad, so sad.  Bruce

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Re: LG TV: image = No. sound = Yes
« Reply #21 on: January 19, 2022,02:15:58 »

 

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