Riddled TV Repair Forum

amal2004 · Joined: 06 Jul 2016 Posts: 2 Location: Maryland

Hi. My Samsung LED TV, Model UN32EH4003FXZA doesnt have a backlight. However with flashlight, In a dark room, I can see it's working. It has sound. I already tried replacing power supply. But it didnt make any difference. Please help me to understand what's the issue here. Thank you

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kuhurdler · Joined: 28 Dec 2006 Posts: 2875 Location: Overland Park, KS

I've worked on a similar model to this one. One of the LEDs in the backlight had failed. Since the lights are in series, it takes out the whole backlight.

Poor design, in my opinion. You can replace one of the LED light strips if you can find a replacement. They were hard to find when I was looking.

You have to take the whole panel apart to get to the lights.

JTS1957 · Joined: 21 Jan 2009 Posts: 2379 Location: Far, Far Away

Unplug each strip and apply your own power supply 20 to 25 volts DC to the strip. Observe proper polarity. IF it only contains open LEDs, the working ones will light up. IF it contains even one shorted LED, then it won't light up. In that case you can test each individual LED in the strip using your own 2 to 3 volt power supply. You may have to carefully pry off the lens to get to LED terminals.

If you decide to go with a new TV or repair this one, don't forget to decrease the back light intensity to as low as you can live with. That alone should increase the lifespan of its LEDs.

amal2004 · Joined: 06 Jul 2016 Posts: 2 Location: Maryland

Hi JTS1957, kuhurdler,
Thank you very much for your responses. kuhurdler, your correct. This is really bad design idea. Since everything else works fine, Im gonna try to fix it instead of buying new one. JTS1957, Thank you for your guidance to how to test LED strips. Since Im new to this, Im bit struggling to remove front LED panel. Anyway I hope I ll be able to fix it. Smile

kuhurdler · Joined: 28 Dec 2006 Posts: 2875 Location: Overland Park, KS

The light strips on the one I was working on had little copper test points you could test each individual LED with a multimeter... without taking the lenses off. Not sure if they are all that way.
I used the diode function of my multimeter... the one that had failed was an open circuit.

Interestingly, my multimeter sent enough power into the LEDs to just barely illuminate them while testing them.

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