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Samsung edge lit screens.

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Turnip:
Hi folks,

Got a Toshiba 40BL702B in where expecting to replace duff Vestel Leds find it's a Sammy screen with edge lit leds.

Screen is LTA400HM13 - Famed for failure.

Wonder if there's a best way to attack it - Chris.

downunder:

Hi Chris,

With much care. LEDs are very close to the edge and raised a bit, I think. Easy to knock off in disassembly. Did just that, but with a bit of

aussie ingenuity was able to short one LED out without upsetting the current sensors. Generally unrepairable.                 Bruce

Turnip:
Hi Bruce,

Thanks for the 'heads up' - Got screen apart without incident finding two Led strips with two Leds duff on one of the four sections.

Guess the next bit is the problem as strips are glued to the aluminium heat sink so have to be removed to get any heat on the back of the strip so can lift duff Leds off and resolder new ones.

Wonder if the glue used is something like 'hot melt' as don't want to try prise the strips off as will wreck them - Chris.

downunder:

All a bit iffey, Chris. Guess they were made not to be repaired. As a last resort you may be able to wiggle faulty LEDs and break them away. This will expose the tiny pads, but getting another LED in may be a challenge. Good luck with it.                       Bruce

Turnip:
Thanks Bruce,

Chap who supplied new Leds suggested 'Hot Melt' to secure them, but didn't mention how to release strips, so suspect a bit of heat the biz.

Might try with a paint stripper, but first think try with my Henly Solon 60 Watt soldering iron clipped to the heat sink sink might do both release and resoldering.

Have a Henly Solon 125 watt iron, but usually use it for sorting seized grease in antique motor ball joints, clipped with a 'G-cramp' for half a day - Seems to work, most times - Chris.

Later - Heated heat sink with 125 watt but Leds wouldn't shift. However, heat enabled me to prise the strip out, and with the iron underneath, Leds could be lifted off strip no problem. Replacing was interesting as thought solder paste might be the biz - It wasn't as the new Led floated about the strip then dropped off due to the heat. Next tried using LMP solder dabbed on the five pads and a drop of liquid flux to ensure soldering. Worked a dream, the Leds didn't shift, soldering looked perfect and the string functioned. Just wondering what to stick it back in with - Could use double sided tape as original but not sure of holding qualities with the stuff I can get, and it's important with maybe 40 watts of heat to dissipate to the heat sink.

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