Source for LED backlight strips?

[Kenny]

Looking for a reliable UK supplier for these. I don't have a part number
but have the panel type number, it's in a 50" LG TV.

Kenny Cargill

 

[N_Cook]

On 17/05/2016 07:47, Kenny wrote:

Looking for a reliable UK supplier for these. I don't have a part
number but have the panel type number, it's in a 50" LG TV.

Kenny Cargill

Is it possible to wire bypass the failed one, and then would there be an
observable weak spot in the illumination?

 

[Kenny]

I had considered trying to repair individual LED's but decided against it, I
have experience of repairing older type TV's but not this type. I have
looked at Youtube video of dismantling these and found it a bit daunting,
especially as it's 50". Have found one source, CHS< listing kit at Ł180 and
a Canadian source at the equivalent of Ł80 but it doesn't say if it's new or
used, have mailed them to ask.
http://www.usefulparts.com/tv-parts/led-tv/led-lights/lc500due-sfr2-led-light-kit-for-lg-led-tv

"N_Cook" wrote in message news:nheerh$3c0$1@dont-email.me...

On 17/05/2016 07:47, Kenny wrote:

Looking for a reliable UK supplier for these. I don't have a part
number but have the panel type number, it's in a 50" LG TV.

Kenny Cargill

Is it possible to wire bypass the failed one, and then would there be an
observable weak spot in the illumination?

 

Yes, bypassing the failed LED will allow the rest of the string to work. Depending on the diffusers used and the pattern of the lens over the LEDs, dead LEDs can be obvious or difficult to pick up. Since the back light driver board monitors current, it reduces the voltage to keep the drop across the remaining diodes within "safe" margins.

Unfortunately, these LED TVs drive the LED string well beyond the safe limit of the LEDs. Often, you'll find several LEDs already shorted in addition to the offending open one. In late model Samsungs, you'll find more shorted than working in many cases. Just did a 2012 46" that had 32 dead out of 44..

You can buy a metric shitload of LEDs out of China for cheap and replace the individual LEDs using a hot air station. Some companies offer a firmware upgrade which reduces the drive to the array. Adjusting the customer controls will achieve the same thing, but I've found that for many reasons, the customer adjustment ends up in default, and that means 100% for the back light setting. I modify the LED drive circuit to reduce the back light by 30 to 40 % at a maybe 10% or so decrease in brightness. No one complains and they don't come back.

 

[Ian Field]

"Kenny" <me@privacy.net> wrote in message
news:NNKdncuibJTgI6fKnZ2dnUU78WHNnZ2d@brightview.com...

Looking for a reliable UK supplier for these. I don't have a part number
but have the panel type number, it's in a 50" LG TV.

My experience with this was finding a TV in the flats bin room that was made
by a well known Turkish company (Vestel).

Apparently LED failure is one of a long list of stock
faults.....................................

Unfortunately I cracked the LCD panel putting it back together, but I
learned a fair bit from the excercise.

Each LED had a plastic lens extruded on, I had to melt these with a
soldering iron to peel them off. The iron wouldn't shift the SMD LEDs.

It took a modeler's pencil blowtorch to shift the dud LED chips, after that
I used a small roll of emery paper to clean off some solder resist and
attach some power LEDs I had to hand.

You can re-touch the PCB around the replaced LEDs with correction fluid.

If its a Vestel - you'll probably find a few more LEDs that tested OK have
given up..............................

 

[Kenny]

"Ian Field" wrote in message news:wAo%y.847680$8r2.99354@fx46.am4...



"Kenny" <me@privacy.net> wrote in message
news:NNKdncuibJTgI6fKnZ2dnUU78WHNnZ2d@brightview.com...

Looking for a reliable UK supplier for these. I don't have a part number
but have the panel type number, it's in a 50" LG TV.

My experience with this was finding a TV in the flats bin room that was made
by a well known Turkish company (Vestel).

Apparently LED failure is one of a long list of stock
faults.....................................

Unfortunately I cracked the LCD panel putting it back together, but I
learned a fair bit from the excercise.

Each LED had a plastic lens extruded on, I had to melt these with a
soldering iron to peel them off. The iron wouldn't shift the SMD LEDs.

It took a modeler's pencil blowtorch to shift the dud LED chips, after that
I used a small roll of emery paper to clean off some solder resist and
attach some power LEDs I had to hand.

You can re-touch the PCB around the replaced LEDs with correction fluid.

If its a Vestel - you'll probably find a few more LEDs that tested OK have
given up..............................

https://www.youtube.com/watch?v=Bf5T2wwtydY
This is the video I watched, it's for a 47" LG, mines 50", I don't have the
space to work like that and wouldn't feel confident dismantling the screen
anyway.
Local shop say they'll look at it and give me an estimate so that's probably
what I'll do, thing is this TV is only 2 years old and the same fault may
recur. I've decided to buy a 55" Sony with 5 year warranty and giving the
LG to a family member if they want to pay for the repair.

 

[Kenny]

"Kenny" wrote in message
news:bpednS2QIckHFqLKnZ2dnUU78dHNnZ2d@brightview.com...

"Ian Field" wrote in message news:wAo%y.847680$8r2.99354@fx46.am4...



"Kenny" <me@privacy.net> wrote in message
news:NNKdncuibJTgI6fKnZ2dnUU78WHNnZ2d@brightview.com...

Looking for a reliable UK supplier for these. I don't have a part number
but have the panel type number, it's in a 50" LG TV.

My experience with this was finding a TV in the flats bin room that was made
by a well known Turkish company (Vestel).

Apparently LED failure is one of a long list of stock
faults.....................................

Unfortunately I cracked the LCD panel putting it back together, but I
learned a fair bit from the excercise.

Each LED had a plastic lens extruded on, I had to melt these with a
soldering iron to peel them off. The iron wouldn't shift the SMD LEDs.

It took a modeler's pencil blowtorch to shift the dud LED chips, after that
I used a small roll of emery paper to clean off some solder resist and
attach some power LEDs I had to hand.

You can re-touch the PCB around the replaced LEDs with correction fluid.

If its a Vestel - you'll probably find a few more LEDs that tested OK have
given up..............................

https://www.youtube.com/watch?v=Bf5T2wwtydY
This is the video I watched, it's for a 47" LG, mines 50", I don't have the
space to work like that and wouldn't feel confident dismantling the screen
anyway.
Local shop say they'll look at it and give me an estimate so that's probably
what I'll do, thing is this TV is only 2 years old and the same fault may
recur. I've decided to buy a 55" Sony with 5 year warranty and giving the
LG to a family member if they want to pay for the repair.

Update on this, was very careful dismantling the screen and using a variable
power supply found a duff LED on 2 of the 12 strips. Easily found using the
part no. on them, expensive at Ł25 each. I've reduced the backlight current
to hopefully make them last longer, it seems LG set the default at maximum!
It wasn't as difficult as I had expected and if doing it again I'd try
replacing individual LED's, I have a few spares now.

 

I just did a 47" LG repair and was surprisingly straightforward. I followed the video (was a very similar TV) and took around hour and a half. Having a friend to help you is great though especially when lifting the LCD out of the frame.

The room I needed was a small (single) bed and a little table to place the TV when disassembling it.

Only one led had blown so I ended up just short circuit'ing it. You can tell a bit that the background is darker but worked well.