LG 50LA6205 Bad Backlight and Bad Panel

**neilc6** · 09-16-2018, 11:23 AM

This TV had a logo flash on plug in which is symptoms of a bad LED backlights. Replaced 4 shorted LEDs and now getting horizontal lines. Tcon ribbons connected one at a time show both vertical and horizontal lines with one side. Confirm this is a bad panel before I scrap this tv?

**Andrew F. Ali** · 09-16-2018, 12:58 PM

Yes...I see a bad panel.

**Davi.p** · 09-17-2018, 10:02 PM

With some work it may be salvaged.. many methods on the field to try.. the easiest one to remove the side tab where the problem starts... also masking with tape on tcon can be tried..

**neilc6** · 09-17-2018, 10:38 PM

No side tabs. Pushed down the tab bonds on the bad side with no change. Scrapped the TV already. Thanks for the input.

**alas3376** · 09-17-2018, 11:28 PM

Bad panel

**neilc6** · 09-20-2018, 11:24 AM

Thanks Davi.p! Was ready to take the TV to recycling and decided one last attempt with the tape method on the tcon ribbon after reassembling the TV. Luckily none of the parts sold yet on ebay. On the side that showed lines (right), I blocked off around 20 pins on the leftmost side and it worked!!

**budm** · 09-20-2018, 11:28 AM

Good works! Lets see how long it will last, at least it is working for now.
Can I get good clear pictures of the T-CON board so may be I can see what those pins are for.

**neilc6** · 09-20-2018, 11:44 AM

Sorry, not the best focussed since it was for the ebay listing. Don't want to take the tv apart again since it has been reassembled about 5 times and I've already busted some plastic tabs.

**budm** · 09-20-2018, 11:53 AM

Thanks for the pictures, at least I can read the PCB and PCBA numbers so now I can go to shopjimmy to get good clear pictures.

**Davi.p** · 09-20-2018, 01:48 PM

OK, where do you have found instructions on how to block signals? I have tried with my 50 inch Hisense w/AUO panel but the result is not perfect, the line still persist due to some gate drv outputs maybe shorted that keep the opposite output low or high, the bigger part of defect is disappeared.. the outer part of the flat is usually reserved for clock signals to the gate drivers.. In mine i have blocked only one signal that disables all the faulty side gate drv, but i will try block others.. maybe it's necessary also to block VGON/VGOFF

**neilc6** · 09-20-2018, 02:00 PM

Saw two youtube videos before about putting tape on the tcon ribbons. One wasn't really clear what he was doing. Tape is actually used to block the pins and not to apply more pressure to the contacts. Another one I recall was to vary the pins blocked and location. Mainly trial and error with the location and width of the tape. I'll see if I can find them since it was awhile ago.

I fixed a Samsung before blocking just a few pins.

https://www.badcaps.net/forum/showthread.php?t=50646

**Davi.p** · 09-20-2018, 05:18 PM

Yes i saw a shopjimmy picture, them are all the gate driver related signals,except Vcom, Vcomr_FB that maybe better to leave connected, i will check..

**neilc6** · 09-20-2018, 11:51 PM

Here is one video

https://youtu.be/j7vl7-vZEL8

**Davi.p** · 09-21-2018, 12:21 AM

yeah i knew that video..

**neilc6** · 09-24-2018, 05:31 PM

2 lines intermittently came back along with a pattern across the whole screen. I replaced the scotch tap with electrical tape and will run for a few days to see if it comes back.

Gdog215 · 12-30-2018, 08:31 AM

Is your tv still working today?

**neilc6** · 12-30-2018, 07:36 PM

Tv came back recently. Another backlight failed even though all inputs were set at 60/100. Repaired and back up and no lines. I would exoect it to last as long as the side tab removal fix.

**RJARRRPCGP** · 12-30-2018, 10:15 PM

What? Another re-badged Sharp panel?

**Davi.p** · 12-31-2018, 01:32 AM

Hi neil, i suspect your customer has mains power line disturbances, next time i suggest you to protect all the screen (backlight and tcon/panel matrix) with TVS diodes or varistors and check the backlight driver's power semicon for cracks in solders and esr of the output el.caps. The suppressors must blow a fuse so your work will be easy and cheap in replacing it.. Bye.

**mmartell** · 01-01-2019, 10:32 AM

What is theory on this type of repair ? I mean, how are these parts of the panel still displaying an image when the signal containing the image information is being blocked with tape ?

09-16-2018, 12:58 PM	#2
Andrew F. Ali Badcaps Veteran Join Date: Jan 2014 City & State: Point Fortin My Country: Trinidad & Tobago Line Voltage: 125VAC 60Hz I'm a: Knowledge Seeker Posts: 2,435	Re: LG 50LA6205 Bad Backlight and Bad Panel Yes...I see a bad panel.

09-17-2018, 10:02 PM	#3
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 2,950	Re: LG 50LA6205 Bad Backlight and Bad Panel With some work it may be salvaged.. many methods on the field to try.. the easiest one to remove the side tab where the problem starts... also masking with tape on tcon can be tried..

09-17-2018, 10:38 PM	#4
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 1,404	Re: LG 50LA6205 Bad Backlight and Bad Panel No side tabs. Pushed down the tab bonds on the bad side with no change. Scrapped the TV already. Thanks for the input.

09-17-2018, 11:28 PM	#5
alas3376 Badcaps Veteran Join Date: Nov 2011 City & State: COTONOU My Country: BENIN Line Voltage: 220V 50Hz I'm a: Professional Tech Posts: 336	Re: LG 50LA6205 Bad Backlight and Bad Panel Bad panel

09-20-2018, 11:28 AM	#7
budm Badcaps Veteran Join Date: Feb 2010 City & State: S.F. Bay area My Country: USA Line Voltage: 120V 60Hz I'm a: Knowledge Seeker Posts: 39,206	Re: LG 50LA6205 Bad Backlight and Bad Panel Good works! Lets see how long it will last, at least it is working for now. Can I get good clear pictures of the T-CON board so may be I can see what those pins are for. __________________ Never stop learning Basic LCD TV and Monitor troubleshooting guides. http://www.badcaps.net/forum/showthr...956#post305956 Voltage Regulator (LDO) testing: http://www.badcaps.net/forum/showthr...999#post300999 Inverter testing using old CFL: http://www.badcaps.net/forum/showthr...er+testing+cfl Tear down pictures : Hit the ">" Show Albums and stories" on the left side http://s807.photobucket.com/user/budm/library/ TV Factory reset codes listing: http://www.badcaps.net/forum/showthread.php?t=24809

09-20-2018, 11:53 AM	#9
budm Badcaps Veteran Join Date: Feb 2010 City & State: S.F. Bay area My Country: USA Line Voltage: 120V 60Hz I'm a: Knowledge Seeker Posts: 39,206	Re: LG 50LA6205 Bad Backlight and Bad Panel Thanks for the pictures, at least I can read the PCB and PCBA numbers so now I can go to shopjimmy to get good clear pictures.

09-20-2018, 01:48 PM	#10
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 2,950	Re: LG 50LA6205 Bad Backlight and Bad Panel OK, where do you have found instructions on how to block signals? I have tried with my 50 inch Hisense w/AUO panel but the result is not perfect, the line still persist due to some gate drv outputs maybe shorted that keep the opposite output low or high, the bigger part of defect is disappeared.. the outer part of the flat is usually reserved for clock signals to the gate drivers.. In mine i have blocked only one signal that disables all the faulty side gate drv, but i will try block others.. maybe it's necessary also to block VGON/VGOFF Last edited by Davi.p; 09-20-2018 at 01:56 PM..

09-20-2018, 02:00 PM	#11
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 1,404	Re: LG 50LA6205 Bad Backlight and Bad Panel Saw two youtube videos before about putting tape on the tcon ribbons. One wasn't really clear what he was doing. Tape is actually used to block the pins and not to apply more pressure to the contacts. Another one I recall was to vary the pins blocked and location. Mainly trial and error with the location and width of the tape. I'll see if I can find them since it was awhile ago. I fixed a Samsung before blocking just a few pins. https://www.badcaps.net/forum/showthread.php?t=50646 Last edited by neilc6; 09-20-2018 at 02:08 PM..

09-20-2018, 05:18 PM	#12
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 2,950	Re: LG 50LA6205 Bad Backlight and Bad Panel Yes i saw a shopjimmy picture, them are all the gate driver related signals,except Vcom, Vcomr_FB that maybe better to leave connected, i will check..

09-20-2018, 11:51 PM	#13
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 1,404	Re: LG 50LA6205 Bad Backlight and Bad Panel Here is one video https://youtu.be/j7vl7-vZEL8

09-21-2018, 12:21 AM	#14
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 2,950	Re: LG 50LA6205 Bad Backlight and Bad Panel yeah i knew that video..

09-24-2018, 05:31 PM	#15
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 1,404	Re: LG 50LA6205 Bad Backlight and Bad Panel 2 lines intermittently came back along with a pattern across the whole screen. I replaced the scotch tap with electrical tape and will run for a few days to see if it comes back.

12-30-2018, 08:31 AM	#16
Gdog215 Member Join Date: Mar 2018 City & State: Philadelphia pa My Country: Usa Line Voltage: 120vac 60 hz I'm a: Knowledge Seeker Posts: 21	Re: LG 50LA6205 Bad Backlight and Bad Panel Is your tv still working today? __________________ You live and you learn right?

12-30-2018, 07:36 PM	#17
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 1,404	Re: LG 50LA6205 Bad Backlight and Bad Panel Tv came back recently. Another backlight failed even though all inputs were set at 60/100. Repaired and back up and no lines. I would exoect it to last as long as the side tab removal fix.

12-30-2018, 10:15 PM	#18
RJARRRPCGP Badcaps Veteran Join Date: Jul 2004 City & State: North Springfield, Vermont My Country: USA Line Voltage: 118-127V 59-63.5 Hz-> actualizo: pérdido de voltaje I'm a: Knowledge Seeker Posts: 6,168	Re: LG 50LA6205 Bad Backlight and Bad Panel What? Another re-badged Sharp panel? __________________ ASRock B550 PG Velocita Ryzen 7 "Vermeer" 5800X 32 GB G.Skill Trident Z Neo F4-3600C18D-32GTZN Sapphire Nitro+ Radeon RX 6750 XT eVGA Supernova G3 750W Western Digital Black SN850 1TB NVMe SSD "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr"!" -mí mismo "There's nothing more unattractive than a chick smoking a cigarette" -Topcat "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

12-31-2018, 01:32 AM	#19
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 2,950	Re: LG 50LA6205 Bad Backlight and Bad Panel Hi neil, i suspect your customer has mains power line disturbances, next time i suggest you to protect all the screen (backlight and tcon/panel matrix) with TVS diodes or varistors and check the backlight driver's power semicon for cracks in solders and esr of the output el.caps. The suppressors must blow a fuse so your work will be easy and cheap in replacing it.. Bye. Last edited by Davi.p; 12-31-2018 at 01:34 AM..

01-01-2019, 10:32 AM	#20
mmartell Badcaps Veteran Join Date: Oct 2013 City & State: Windsor ON My Country: Canada I'm a: Knowledge Seeker Posts: 3,043	Re: LG 50LA6205 Bad Backlight and Bad Panel What is theory on this type of repair ? I mean, how are these parts of the panel still displaying an image when the signal containing the image information is being blocked with tape ?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode