Working backlight and sound, but no picture (55LA6208)

[dick_barton]

Re: Working backlight and sound, but no picture (55LA6208)

hello Paul

over years till now, never found IPS Panel from LG get any operation Fault unless faced visibility damage by human.

the method where you use over this forum disconnect T-CON ribbon to Panel wouldn't work , because the feed are absolute different. its mean one half will be white but when you disconnected the other one only both side will be black,

there are no problem with panel.. as i said if it not had damage on right side down when you facing the panel

Hello Diah,
I think I understand what you are saying but......why would the Tcon voltages be present when it is not connected to the panel?
Thanks

[Alastair E]

Re: Working backlight and sound, but no picture (55LA6208)

Ive seen dozens of dead LG panels--prob the worst of the bunch the 40" and 42" are notorious--utter turds....
--and--Not damaged or cracked, just dead just like this, no image/nothing on screen with known good t-con, psu and main

[Diah]

Re: Working backlight and sound, but no picture (55LA6208)

why would the Tcon voltages be present when it is not connected to the panel?
Thanks

which voltage present ??? did you think this measurement listed over here are reason to think IPS panel fault ? ?? if there no broken lead at right side down of the panel or the right side ribbon cable pin between T-CON and panel .. ... also who know that backlight working LOL. i have at home LA6208 za 2 time already replaced LED

Ive seen dozens of dead LG panels--prob the worst of the bunch the 40" and 42" are notorious--utter turds....
--and--Not damaged or cracked, just dead just like this, no image/nothing on screen with known good t-con, psu and main

dear Alastair : you were right.. but not IPS panel. check again please.

[Diah]

Re: Working backlight and sound, but no picture (55LA6208)

this is the service manual for this serial

[Carlozzz]

Re: Working backlight and sound, but no picture (55LA6208)

So what is the best thing I can do right now? Can I measure something? I really want to know what board is broken and why I don't see any picture.
I already changed the t-con board, so that is not the problem.

[budm]

Re: Working backlight and sound, but no picture (55LA6208)

We already know that you DO HAVE Backlights per post 1 and post 3 (it is still a black screen with led lighting behind it.), but the VGH goes down to 0V when he ribbon cables between the panel and the T-con board, and when you disconnect the cable the VGH comes back to normal level again, so it is either the TFT drive ICs on the panel shorted out or the caps on the tab bonding board is/are shorted out.
You can check the resistance between GND and the VGH test point to see what you get when you have the ribbon cable in place and not in place. Something is killing the VGH power supply or the VGH power supply is too weak even though you had replaced the T-CON BUT with a GOOD ONE?.

[ReeceyBurger123]

Re: Working backlight and sound, but no picture (55LA6208)

We already know that you DO HAVE Backlights per post 1 and post 3 (it is still a black screen with led lighting behind it.), but the VGH goes down to 0V when he ribbon cables between the panel and the T-con board, and when you disconnect the cable the VGH comes back to normal level again, so it is either the TFT drive ICs on the panel shorted out or the caps on the tab bonding board is/are shorted out.
You can check the resistance between GND and the VGH test point to see what you get when you have the ribbon cable in place and not in place. Something is killing the VGH power supply or the VGH power supply is too weak even though you had replaced the T-CON BUT with a GOOD ONE?.

Careful dont trigger Diah lol