LG 42LN5400 Power but no backlight, picture or sound

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

So I figured out how to properly get the LED strips off the TV and disconnected. The last question I have is where do I find the panel number? I just want to make sure I get the correct LED strips.

[budm]

Re: LG 42LN5400 Power but no backlight, picture or sound

There should be a sticker on the back of the panel for the LCD panel model number. Show us the pictures of the whole back side of the TV may be I can see the sticker.

[diif]

Re: LG 42LN5400 Power but no backlight, picture or sound

The strips are usually stuck down with double sided tape and clip into that green vertical strip. Warm up the back panel with a hair dryer to soften the adhesive.
Panel number is usually on a sticker on the back of the panel.
Are you replacing with guaranteed brand new strips or second hand, no point in swapping them all if so.

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

The strips are usually stuck down with double sided tape and clip into that green vertical strip. Warm up the back panel with a hair dryer to soften the adhesive.
Panel number is usually on a sticker on the back of the panel.
Are you replacing with guaranteed brand new strips or second hand, no point in swapping them all if so.

Well I have seen second hand ones on eBay but am a little skeptical to purchase them. If these Tv's had issues with the LED's I don't know how much I trust second hand ones. I was planning on getting them from shopjimmy. Also I see one that is burnt badly but don't know if there are any others that are bad so I would hate to buy just that strip and need to buy more. This is my first time replacing LED's so I'm open to suggestions as always budm has been a great help and i also appreciate your input so if either of you has any suggestions as to if I should buy the LED's from shopjimmy or if they are ok to buy off eBay I would appreciate it and would trust your suggestions.

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

There should be a sticker on the back of the panel for the LCD panel model number. Show us the pictures of the whole back side of the TV may be I can see the sticker.

I didn't even realize it was on the back of the TV case. I thought it was on the back of the panel. I was able to find it. It was a big sticker that said LG display so that was my stupidity for not seeing it. Thanks for the help

[dskall]

Re: LG 42LN5400 Power but no backlight, picture or sound

There should be a sticker on panel

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

Ended up ordering the LED's from shopjimmy.com. The correct LED's were out of stock but they gave me an alternate set of LED's that are supposed to work so I ordered them and some double sided tape. Once everything gets here I will put it back together and let you know the how it goes. Can I replace the led' s and turn it back on before I put it all back together?

[dskall]

Re: LG 42LN5400 Power but no backlight, picture or sound

If you connect all the boards minus panel

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

Just wanted to thank everyone who helped me diagnose this TV. I received the new LED's Wednesday, installed them and put everything back together, updated the firmware and the TV is back in working order. It feels good to be able to take one that someone had in the trash and bring it back to a working useable TV.

[budm]

Re: LG 42LN5400 Power but no backlight, picture or sound

Thanks for the follow-up on the repair.

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

So in my haste of putting the TV back together after replacing the LED's I forgot to put the white plastic pin clips on the white LED surround. Is it worth tearing the TV back apart to put them back or should I just not worry about it?

[heavymachines]

Re: LG 42LN5400 Power but no backlight, picture or sound

Those help support the diffuser sheets and lcd from flexing too much also help hold the white sheet to the metal back. It probably be ok without em for a min but could potentially cause problems in long run if back sheet or defuser sheets sags too much from heat or gravity.

[dhoff024]

Re: LG 42LN5400 Power but no backlight, picture or sound

I will take it back apart today or tomorrow and put them on and put it back together. Thanks for the input

[DjKrish]

Re: LG 42LN5400 Power but no backlight, picture or sound

I have a problem with this same tv as well, no backlight but theres
image and sound. Tested the voltage on the PSU, theres voltage present on both + points which is 200 plus on side and 150 plus on another side. Theres no flash when turn on the tv either. Is the LED stripes shorted for good inside the panel? Or the LED driver dead?

[dskall]

Re: LG 42LN5400 Power but no backlight, picture or sound

Replace your bad led's

[budm]

Re: LG 42LN5400 Power but no backlight, picture or sound

I have a problem with this same tv as well, no backlight but theres
image and sound. Tested the voltage on the PSU, theres voltage present on both + points which is 200 plus on side and 150 plus on another side. Theres no flash when turn on the tv either. Is the LED stripes shorted for good inside the panel? Or the LED driver dead?

You have open circuit in the LED string.

[nrbrandt]

Re: LG 42LN5400 Power but no backlight, picture or sound

I've got this same model of TV and I could use some help diagnosing it. When you turn the TV on, it's hit or miss whether the back light comes on or not. When it does turn on, you can bring up the menu (I don't have anything hooked to it to know if the sound works).

Voltages from the power supply board to main board appear to be normal. The 24 volt pin registers 24.3. DRV ON registers 3.2 and PDIM1 and 2 are both 1.1v.

On the connector to the LED strips I get (from left to right on the connector) 112v, 28v, 74v, and 19v if the back light turns on. If not I get 56v, 0.1v, 56v, 10v.

Once you've gotten the TV to turn on, it won't come on again without being unplugged first.

Is this bad LED strips or else what do I need to check next?