LG 47LN5400 TV Backlight problem

[budm]

Re: LG 47LN5400 TV Backlight problem

What are the spec of the replacement LED?

[Thorn]

Re: LG 47LN5400 TV Backlight problem

Same issue here. Sound still see picture but no back light. traced it back to bad LEDs, replaced all. Problem still persisted, replaced power supply just in case it had some unseen issue(I believe the inverter is part of it) no change.. Tore it back down to LEDs, turns out one led bad on one strand...these were brand new! :/ got a replacement for that strand, tested all LEDs again,all test good now, but problem persists!
One thing that is happens when you turn it on now and you get the notorious "flash, then nothing" 3 led strands are not flashing up even though they test good with direct power Scratching my head. I tested all LEDs, output voltage on PSu, and tested on the leads on the ribbon cable from the main board, all voltage seem right except the bottom lead on ribbon(blue cable ) tested 3.27v where it is printed 3.5v specs? Is there some small issue on the main board?

[CapLeaker]

Re: LG 47LN5400 TV Backlight problem

Perfect!

[SurrealMustard]

Update

The two L2 Led strips arrived and I installed them right away. I also used the remaining good Leds from the strips that were replaced to replace the bad ones on the other strips throughout the set and now everything is working 100%!

[SurrealMustard]

(Led) Strips!

Update: Led strips have been ordered. We should find out how well this'll work either late this week or early next week.

Yeah, its plastic but as you said the same thickness of paper so it could potentially set fire. Also do you they would bother putting good leds in their Tv's, really ? They wont because that way they make less profit and Tv would last longer meaning that well it wont fail as quick so people wont have to buy another off them. Its a total joke the way everything is going all cheap crap that doesnt last. If its not the Leds its the Lcd glass which is not fixable.

Fair enough. They actually hit the mark perfectly on this one in that case: catastrophic failure (most folks would be too afraid to completely dismantle their flatpanel like this) just outside the 1 year warranty period. Bonus points if the customer buys another LG to replace it.

[CapLeaker]

Re: LG 47LN5400 TV Backlight problem

I like the way Reecey talks as if he is 60 years old. Lol.
Thinks have been mad cheaply and like crap since before you were born.
I didn't have a color TV till 1982. ��
Do you know what a rotary phone is? Lol

Lol

[ReeceyBurger123]

Re: LG 47LN5400 TV Backlight problem

Lol I know how these people/compaines work all of them are greedy sly bastards like almost everyone now a days. Whats a rotor phone too ? Narr just messing

[Malachi]

Re: LG 47LN5400 TV Backlight problem

I like the way Reecey talks as if he is 60 years old. Lol.
Things have been made cheaply and like crap since before you were born.
I didn't have a color TV till 1982. ��
Do you know what a rotary phone is? Lol

[ReeceyBurger123]

Re: LG 47LN5400 TV Backlight problem

Yeah, its plastic but as you said the same thickness of paper so it could potentially set fire. Also do you they would bother putting good leds in their Tv's, really ? They wont because that way they make less profit and Tv would last longer meaning that well it wont fail as quick so people wont have to buy another off them. Its a total joke the way everything is going all cheap crap that doesnt last. If its not the Leds its the Lcd glass which is not fixable.

[SurrealMustard]

Flaming hot Leds

Holy shit ! I think that Led is bad right ? Yeah you will need to also repair the return line trace (small trace next to it) that it burnt if not you wont get any Bl still. Keep us updated on what happens. Would have never expected one to get that bad though it must have gotten very hot.

I guess you found it no problem!

You got that right! And on a <2 year old set too. I mean, that papery layer that goes around the backlights is exactly that - paper. This thing could've burst into flames. You'd think that being cut a break in not having to source CCFL lamps for their flatpanels anymore that manufacturers would at least get quality Leds, but apparently not.

Anyway, the plan for this one will be to buy two L2 strips. One to replace the strip that was obviously burned, and the other to extract Leds off of to repair the handful of other Leds on the other various strips that have shorted out (but not yet started the television on fire).

[CapLeaker]

Re: LG 47LN5400 TV Backlight problem

I guess you found it no problem!

[ReeceyBurger123]

Re: LG 47LN5400 TV Backlight problem

Holy shit ! I think that Led is bad right ? Yeah you will need to also repair the return line trace (small trace next to it) that it burnt if not you wont get any Bl still. Keep us updated on what happens. Would have never expected one to get that bad though it must have gotten very hot.

[SurrealMustard]

ah ha!

Well, I finally disassembled the panel. Take a look at the first picture and see if you can guess what the problem might have been .

It was obviously pretty seriously burned, but after doing the infamous "scratch n sniff" test with a multimeter, I found various other leds on the board that were shorted and one or two that weren't, but were in the process of dying. I'll probably buy two strips on eBay - one to replace the one that completely fried and one to extract Leds off of to replace the other dead modules on the other strips

[Malachi]

Re: LG 47LN5400 TV Backlight problem

Yes. They are listed on eBay. I don't know if I'm allowed to link to it here.
I have them listed for what I paid for them. $70.
Sent you a pm.

[SurrealMustard]

inquiry

I'm here in Ohio. I have a full set of LEDs to a backlit Emerson that I cracked the screen on. Lol.

Would you be willing to sell them? Will they work with the LG?

[Malachi]

Re: LG 47LN5400 TV Backlight problem

I'm here in Ohio. I have a full set of LEDs to a backlit Emerson that I cracked the screen on. Lol.

[SurrealMustard]

good to know

The craigslist one will be fine and will mean you have other replacements on hand.

That's good to know. What if nobody is selling or giving away any cracked LED-backlit LCDs locally? Can the Leds be acquired any other way?

[ReeceyBurger123]

Re: LG 47LN5400 TV Backlight problem

The craigslist one will be fine and will mean you have other replacements on hand.

[SurrealMustard]

multimeter hack! :-)

Check out my video:

https://m.youtube.com/watch?v=RxwdC7V5Ue0

Interesting. So the multimeter will be enough to test the existing lamps, which will be helpful. If I don't currently have a television with a dead panel, could I just go and buy any LED-backlit LCD with a cracked screen from Craiglist for a few dollars and expect the Leds to work? If not, where would be a good place to get replacements?

[ReeceyBurger123]

Re: covering bases

So just to recap, what kind of Leds are recommended for these sets? Also, can they be tested without a bench power supply?

Check out my video:

https://m.youtube.com/watch?v=RxwdC7V5Ue0