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Old 09-12-2021, 04:49 AM   #1
ioanban
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Default old LG 47LE8900 not turning on

Hi guys,
I've just received an 10 years smart LG 47LE8900 from a friend and i can't seem to find out why i don't have any image or sound . It has only stand-by light .
I have checked all voltages on the power board, I have cleaned all ribbon cables, i have checked all fuses , i have done a visual inspection on all capacitor and they look ok.

I've attached some pictures with all the boards.
Give me some idea's what can I do to get it working again.

Thank you,
Attached Images
File Type: jpg IMG_0890.jpg (734.0 KB, 7 views)
File Type: jpg IMG_0895.jpg (1.13 MB, 13 views)
File Type: jpg IMG_0896.jpg (985.0 KB, 6 views)
File Type: jpg IMG_0898.jpg (1.05 MB, 9 views)
File Type: jpg IMG_0899.jpg (930.4 KB, 6 views)

Last edited by SMDFlea; 09-12-2021 at 07:47 AM.. Reason: LG 47LE8900
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Old 09-12-2021, 06:48 AM   #2
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Default Re: old LG not turning on

Very often these LG suffers from bad CPU soldering. You need to try a reballing from a specialized center, this is one of the best models from LG so it will worth some spending, after made it a new bigger heatsink is suggested, or a fan.. it is not truly old for me..
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Old 09-12-2021, 07:18 AM   #3
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Default Re: old LG not turning on

They usually do start up if the BGA soldering is bad. Disconnect the cable between main board and tcon. Does it power up then?
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Old 09-12-2021, 08:39 AM   #4
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Default Re: old LG 47LE8900 not turning on

Are you referring to this particular model? Because in other LG it doesn't start..
A quetion, when you push power button does it makes some status led blinks?

Last edited by Davi.p; 09-12-2021 at 08:42 AM..
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Old 09-12-2021, 10:32 AM   #5
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Default Re: old LG 47LE8900 not turning on

The couple I had to work on would power up from standby but had no picture, no sound.
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Old 09-12-2021, 12:44 PM   #6
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Default Re: old LG 47LE8900 not turning on

Quote:
Originally Posted by Davi.p View Post
Are you referring to this particular model? Because in other LG it doesn't start..
A quetion, when you push power button does it makes some status led blinks?
I'm talking about this particular model 47LE8900 when i push the power button it turns the front touch buttons on and the logo, nothing else. No backing light or anything else.
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Old 09-12-2021, 12:46 PM   #7
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Default Re: old LG 47LE8900 not turning on

Quote:
Originally Posted by Th3_uN1Qu3 View Post
The couple I had to work on would power up from standby but had no picture, no sound.
Mine power's up but i dont have picture or sound, it might be the same problem !
What was the solution ?
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Old 09-12-2021, 12:50 PM   #8
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Default Re: old LG not turning on

Quote:
Originally Posted by Th3_uN1Qu3 View Post
They usually do start up if the BGA soldering is bad. Disconnect the cable between main board and tcon. Does it power up then?
I've tried but it stays the same
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Old 09-12-2021, 01:44 PM   #9
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Default Re: old LG 47LE8900 not turning on

Does the lights blinks or stays on for some seconds and then shuts off? Anyway this doesn't change much, i confirm the diagnosis.
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Old 09-13-2021, 01:53 PM   #10
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Default Re: old LG 47LE8900 not turning on

LE, LV, LW, and LS series suffers from bad bgas. Lot of ebay repair services if you google your model. To confirm, you can heat up the cpu with a hair dryer before plugging in.
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Old 09-16-2021, 01:02 AM   #11
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Default Re: old LG 47LE8900 not turning on

Quote:
Originally Posted by Davi.p View Post
Does the lights blinks or stays on for some seconds and then shuts off? Anyway this doesn't change much, i confirm the diagnosis.
Yes,
The lights are staying on. No blinking .
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Old 09-16-2021, 01:10 AM   #12
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Default Re: old LG 47LE8900 not turning on

Quote:
Originally Posted by neilc6 View Post
LE, LV, LW, and LS series suffers from bad bgas. Lot of ebay repair services if you google your model. To confirm, you can heat up the cpu with a hair dryer before plugging in.
I will try to get it heated at around 200 degrees and see if that works. Thank you
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Old 09-16-2021, 05:32 AM   #13
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Default Re: old LG 47LE8900 not turning on

SOLVED !
I have backed the main board at 200 degrees Celsius for about 10 minutes and after i left it cool down I got it back in the tv and i was pleasantly surprised to see that it works (I have done it before with other main board without success ) .

Thank you for the support guys!
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Old 09-16-2021, 06:20 AM   #14
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Default Re: old LG 47LE8900 not turning on

Ley us to know when the problem will return eventually..
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Old 09-17-2021, 06:18 PM   #15
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Default Re: old LG 47LE8900 not turning on

I can source replacement processors for these, the BGA rework side of things is up to you though as I no longer have a rework station.
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Old 09-18-2021, 02:09 AM   #16
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Default Re: old LG 47LE8900 not turning on

The unique the processors that you find are probably second hand..
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