Re: LG 42LN578V picture but no backlight

The LED layer itself is the front layer its around 3-5mm in thickness. Behind that is just a plastic sheet that is used as a diffusion material for the led's to spread the light uniformly. There are then lots of acetate type layers behind that. It would be possible to transplant a working LED as I did using a set with a failed backlight but these are much harder to source than those with broken screens. I was lucky that I had a failed backlight, had it have been a broken screen the TV is near worthless.

Re: LG 42LN578V picture but no backlight

There is no 'inner' panel I'm afraid, just the lcd and then several plastic layers. You would need to replace the lcd panel and getting an undamaged one will be pretty difficult. Probably more than the cost of a second hand set.

Re: Uneven LED backlight possible fix

On LG they are held in place by little metal tabs

I'm no expert but after recently playing with an led screen with a dodgy string of led's I got to see the inner workings. I was guessing that all the little layers not being correctly positioned was the cause of uneven backlight. I have seen a post about using a microfibre cloth to smooth out the inner layers. Whilst in bed this morning I noticed that my tv screen (turned of was reflecting the window frame but was not reflecting it as a rectangle more an extreme concave. This got me to thinking that inner layers may have been making contact with the screen or each other. I had tried the cloth...

Re: LG 42LN578V picture but no backlight

Ok the bad news:
PSU didn't fix it, there was a string of led's faulty when I took it apart
Good news:
I bought the same tv from gumtree (100 mile drive last night) with a cracked screen for £20, swapped my decent lcd panel over (probably some dust behind but oh well) and taddaaaa!...

Re: LG 42LN578V picture but no backlight

I will buy a new board as they are pretty cheap used. It would be a miracle if it fixed it but a lovely surprise Will post back when it arrives. Thanks guys

Re: LG 42LN578V picture but no backlight

@nomoresonys, I do yes. I am not great with them though

Re: LG 42LN578V picture but no backlight

Pictures as requested. Crawley is a great place, not at all "creepy"
Thanks for any help offered...

My neighbour just gave me their LG 42LN578V that with a torch shows the image perfectly clear and crisp but the backlight is not working, I have also not heard any sound from it either. I presume the LED driver is built into the screen itself as it seems the PSU powers the backlight rather than a separate board. Can anyone advise diagnosis steps? I was going to buy a new Power board as it makes a little bit of a whistling sound but don't want to throw money away on a none repairable set.
Thanks guys

Re: How to buy a main board for LG42lf66? which code shall i look for..

Sorry to drag up an old post but I too am looking for this board if anyone still has one for sale? If not I have the rest of the TV for spares if anyone needs anything before I tip it?