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New old topic LED back lights failing.

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bonesy:
Hi guy's,new/old topic led back lights.I'm amazed how many of these sets,from all manufacturers are now turning up with failed LED's.This week alone I've had around 9 sets in with duff LED's.The smallest a 32" Samsung,but most 40-42",from various makers.Now there's a good supply of different LED's available,it's getting more cost effective repair solution.
Just interested in how others are finding this & how you go about repairing.
I use to just buy new strips from CHS,but since they've closed,I've been buying diodes & replacing the duff ones & any that look stressed.Sometimes,if you remove a strip & look at the back,you can see a discoloration,heat mark,although if you put a voltage across the LED it lights o.k.I tend to change these ones out as well.I also take a fresh LED,find the voltage at which it will just light somewhere around 2.6-2.8 volts,so just lit but dim,then do the same with the ones fitted to strip,you will usually find they will light dim at around 2.8 volts,any that are very dim or barely lit I change out.with these dim LED's if you apply around 3 volts,they do light brightly,as normal,but my thinking is I want to avoid bouncers,taking the screen apart again ,I think it helps point towards diodes that might be on their way out.
It would be nice to know what other repairers are doing.
all the best John.

Turnip:
Hi John,

Agree about checking/replacing any Led that looks duff'ish - Trouble is, most look a bit distressed when others have popped. Only ever used individual diodes rather than strips, and changing 'em is a real nice job once you have the knack.

Trouble for me is in handling 47 and 55 inch screens, as just the smallest chip on the edges means failure, and the fly caught on the announcers nose in high summer is another drawback after reassembly.

Thinking of using a specific area (the garage) clear of anything else, and using a couple of redundant doors on folding legs so I have the space needed to shuffle stuff about.

As to possible failure - I Suggest the set is 'scrap' that might be redeemed (give a 20% chance) as folks can get touchy when a recently bought expensive set has expired prematurely. Folks who don't agree to terms are welcomed to go try elsewhere - Chris.

sinclairtv:
I think one of the most important points is to make sure you have a good flat space to lay down the screen and diffuser panels. Iv a supply of LED strips so whenever possible I'll change the entire strip. Failing that I'll remove the diode and piggyback a cut LED onto the panel. Biggest Iv done is a 47 but I always tell the customer its kill or cure. I ease a large piece of cardboard gently below the screen and - hopefully - lay it down on a clear bench. I had a 42in Samsung a while back with an LED burnout (see image), obviously scrap so as an experiment I tried to gently remove the screen with just my hands, but it snapped. So back to the cardboard again.

bonesy:
Wow,never seen one that bad.Biggest I've done is 50" & I use a sheet of card that I slide under the screen,I also got some anti static gloves I put on,also stops the dreaded finger prints. I've also got a small air compressor so I blow out  around lights & white back sheet,then the back & front of the sheets,I do my best to not let them separate.I also warn the customer it's kill or cure & then well hope for the best.
When ccfl was in use I think I only ever changed a hand full of tubes,crazy,one step forward two back.

vlado66:
 :96:

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