Individual led source for backlight repair - anybody have samsung strips?

[whitejohnny71]

Hi folks!

Just found a samsung lcd tv with no backlight, power supply tests ok, backlight can be forced on by shorting past part of the string, so I disassembled the panel and found that I had 3 bad leds between the two strips.

Does anybody have a source for generic lcd tv backlight leds?

Or a strip pulled from a samsung with a few working ones?

Thanks for reading, and thanks to all for making this such a great site and forum!
john

[budm]

Re: Individual led source for backlight repair - anybody have samsung strips?

https://www.badcaps.net/forum/showpo...&postcount=278

https://www.badcaps.net/forum/showthread.php?t=51251

[whitejohnny71]

Re: Individual led source for backlight repair - anybody have samsung strips?

https://www.badcaps.net/forum/showpo...&postcount=278

https://www.badcaps.net/forum/showthread.php?t=51251

Than you Bud! I searched a few times from google and on the site, but i guess I didn't drill down the results hard enough..

[dick_barton]

Re: Individual led source for backlight repair - anybody have samsung strips?

Perhaps if you posted pictures of your led strip and the information printed on the strip could help to identify replacements.

[vinceroger69]

Re: Individual led source for backlight repair - anybody have samsung strips?

also what country are you in? as we maybe able to recommend various sources.

[whitejohnny71]

Re: Individual led source for backlight repair - anybody have samsung strips?

Hi folks, it was a un32eh4003 samsung tv. Turned out I have a few samsung strips in my recycler pile, so I swapped the LEDs out (iron & hot air rework tool) and its been running for a couple hours now.

I've attached a pic of the strips. It turned out three 9volts in series will light the whole 9 LED strip.

To determine the bad LEDs I first connected a 9volt battery to my meter's probes and then started with the black probe on the strip's minus terminal. Then I used the red probe's tip to scratch off a little of the coating over the copper traces on the pcb strip. It took a minute to work out test points around each LED. I found 3 dead ones.

To harvest the replacements I heated the stick around the lens and slid a 'spudger' underneath - the lens popped right off. Then I heated the back of the strip behind the led with a broad chisel tip iron and hot air and within 20 seconds I was able to slide the led off the donor strip. Then I verified anode/cathode orientation and soldered them on.

Then, it didn't work - so I found the bad solder joint and corrected it LOL

Tested and reassembled for burn-in, still running

Thanks again guys!

[dick_barton]

Re: Individual led source for backlight repair - anybody have samsung strips?

Looks like a good outcome. Just to give the standard warning to turn the backlights down as low as you can so as to enhance the lifetime of the led's.

[budm]

Re: Individual led source for backlight repair - anybody have samsung strips?

"I've attached a pic of the strips. It turned out three 9volts in series will light the whole 9 LED strip.

To determine the bad LEDs I first connected a 9volt battery to my meter's probes and then started with the black probe on the strip's minus terminal. Then I used the red probe's tip to scratch off a little of the coating over the copper traces on the pcb strip. It took a minute to work out test points around each LED. I found 3 dead ones."
Be real careful when testing any LED without current limiting, for example, if the 9-LED strip has one or more shorted LED so when you apply 27VDC to the strip, the good LEDs can be damaged due to over current because of the shorted out LED/s.

[102mm]

Re: Individual led source for backlight repair - anybody have samsung strips?

"I've attached a pic of the strips. It turned out three 9volts in series will light the whole 9 LED strip.

To determine the bad LEDs I first connected a 9volt battery to my meter's probes and then started with the black probe on the strip's minus terminal. Then I used the red probe's tip to scratch off a little of the coating over the copper traces on the pcb strip. It took a minute to work out test points around each LED. I found 3 dead ones."
Be real careful when testing any LED without current limiting, for example, if the 9-LED strip has one or more shorted LED so when you apply 27VDC to the strip, the good LEDs can be damaged due to over current because of the shorted out LED/s.

How do you limit the current when testing the strip?

[dick_barton]

Re: Individual led source for backlight repair - anybody have samsung strips?

How do you limit the current when testing the strip?

Best way is to use a power supply which has current limit or use the led strip testers that are now on the market.