LG 39LB561V flash backlighting

[Moddingscreen]

good morning to all, I'm going crazy, a lg 39lb561v the backlight emmette a flash for 1 second and then dark, the pcb power EAX65423701. I checked the following voltages on pins 12 v 24 v and 3.5 v are present pwr on-3.5 v and dvron - 3.1v on the output pins of the led I 0v! What can I check? the capacitor next to the LED connector measures 108v

[budm]

Re: LG 39LB561V flash backlighting

You need to upload good clear straight shot of the whole back side of the TV showing all the boards, and the pictures of the whole power supply LED driver board.

[freakaftr8]

Re: LG 39LB561V flash backlighting

Probably backlighting issues. One goes out, you see the outcome as system tries to energize but balancing off.

I could pull a 39" panel in my sleep. Check out the backlights.

[Moddingscreen]

Re: LG 39LB561V flash backlighting

here they are!

[Moddingscreen]

Re: LG 39LB561V flash backlighting

I tried to give them 100v voltage in DC taken directly from the capacitor alongside, the result is the same! I have the dead led?

[budm]

Re: LG 39LB561V flash backlighting

If you turn off the TV and remove the LED connector then leave the meter (set the meter scale so it can read higher than 200VDC) probes on the two legs of that cap C801 (33uF 350VDC) then turn on the TV while keeping an eye on the meter, you should see the Voltage go up much higher than 200V and then it should go down to 108V (this is the feeding Voltage to the Boost converter).
More likely that you have shorted out LEDs that is why you see the backlights flash on for seconds and then go black due to over current shutdown.

[Moddingscreen]

Re: LG 39LB561V flash backlighting

I removed the panel, and I found a dead LED, I will try to replace that. attached photo

[Andrew F. Ali]

Re: LG 39LB561V flash backlighting

I have found with LGs that after LEDs replacement you would need to turn down the backlight level to 60%. However, I've had some callbacks even though backlight was adjusted to 60%. The final and outcome for me is that all the strips should be replaced and that seems to hold out, so far.

[Moddingscreen]

Re: LG 39LB561V flash backlighting

I reassembled the panel, but now I have this! what did I do? Did I mess up?

[jasonr2000]

Re: LG 39LB561V flash backlighting

do you get any image on the lower half ?

[Moddingscreen]

Re: LG 39LB561V flash backlighting

yes but it is not aligned with the rest of the image

[Moddingscreen]

Re: LG 39LB561V flash backlighting

I ruined the panel according to you? and yet the removed and reassembled with extreme care and precision, the only stupid thing I have done is to connect the flat ldvs with the power plug inserted. I throw it away or can it be that in short the t-con?

[Moddingscreen]

Re: LG 39LB561V flash backlighting

can nobody help me?

[tw2005]

Re: LG 39LB561V flash backlighting

Does sympathy help? I killed my first 50" LG LED last week. Did it differently and bolted the boards and power supply back on before the panel. Somehow I had a discharge through me, into the case whilst holding the top right corner of the panel.
I now have no display, diconnected righ Tcon ribbon anleft came on perfect. Looks like I spiked the right half of th epanel.

For you, I can take a guess due to my LCD inexperince but thos little ribbons/tabs on the right and left sides that are taped to the chassis.. any of those damaged or cut?

They looked like terminations to me .

[Moddingscreen]

Re: LG 39LB561V flash backlighting

I had also thought about those tapes, but they are perfect they have no cut or malformation