Samsung UN46ES6100 / no backlight

[Plaxus]

I am trying to diagnose/repair a Samsung UN46ES6100 LED TV with no backlight. I have done the flashlight test and there is an image on the screen. Audio works fine as well.

Testing the voltage from the BN44-00502a power supply to the LED backlight strips, (see attached photo) - the readings are as follows:

both R+ = fluctuating between 250-265V

R- and L+ = fluctuating, around 1-2V

both L- fluctuating between 1-3V

My understanding is that these should be steady DC voltage, not fluctuating. I suppose the fact that it's only reading 1V in the Left side of the circuit is the problem. How would I go about further isolating the problem?

[CapLeaker]

Re: Samsung UN46ES6100 / no backlight

probably bad backlights. The LEDs are current controlled, not voltage controlled.

[Plaxus]

Re: Samsung UN46ES6100 / no backlight

I'll admit I'm a noob, but just for my understanding should the voltage from the board not be identical through left and right? I forgot to mention I have the same dissimilar readings with the cable disconnected as well.

So there are the backlight parts: https://www.tvparts.ca/tvdetail.php?id=10707

There are no LED bulbs, that I can see, only the left and right strips.
Part #s BN96-21462A, and 63A

[R_J]

Re: Samsung UN46ES6100 / no backlight

If you look at the bottom of the board you will see your answer.
pins 2,3 (R+) are the supply voltage for the led string, pins 5,7 are connected together, only to join the two led strings. pins 9,10 are the return line. You have an open led string, thats why you have the high fluctuating voltage on pins 2,3 and not any others.

If the leds were all working you would have about 190v on pins2,3. approx 90v on pins 5,7 and likely 10~15v on the return pins 9,10.
What do you mean you can see no "LED bulbs" what did you expect?
The LED'S are mounted to the LED strips.

[budm]

Re: Samsung UN46ES6100 / no backlight

Are you testing those Voltages with the LED connector in place?
What did you for meter ground probe?

[Plaxus]

Re: Samsung UN46ES6100 / no backlight

Are you testing those Voltages with the LED connector in place?
What did you for meter ground probe?

Those reading are with the connector in place, but I have tested with the connector unplugged as well.
I have my multimeter black probe on the tv chassis.

[Plaxus]

Re: Samsung UN46ES6100 / no backlight

What do you mean you can see no "LED bulbs" what did you expect?
The LED'S are mounted to the LED strips.

I was expecting to see strips running horizontally across the tv, similar to the ones in this image.

[R_J]

Re: Samsung UN46ES6100 / no backlight

In this panel the screen is edge lit. It could be a simple as a bad connection or likely one of the led's is open.

[budm]

Re: Samsung UN46ES6100 / no backlight

Based on the Voltage reading on post 1, it has open circuit in the LED string.

[neilc6]

Re: Samsung UN46ES6100 / no backlight

The ES series are slim edge lit models and tricky to replace the backlights. First one I did, a 55", I damaged the panel in the corner by forcing the frame in place and it was probably not sitting flush. It was tolerable but some double sided tape on the edges had floated into the screen area and I cracked the screen lifting the corner up by the weakened area to move the tape back. Was planning to keep the TV for myself.

Here are your strips from a trusted seller. Looks like it could be 2D with 6 pin connector https://ebay.us/HoYUef or 3D with 10 pin connector https://ebay.us/x0ssiG

Some tips -

The small Philips screws holding the panel edge cover and bezel strip very easily. You will need to drill out if you do.

There is double sided tape/rubber on the edges holding the panel to the plastic bezel.

There is very little edge to the bezel holding the lcd panel. Make sure it is sitting flush before replacing the outer frame. Do not force the frame in place which is how I cracked my screen.

[Plaxus]

Re: Samsung UN46ES6100 / no backlight

I appreciate the help from everyone.

I opened it up the TV to get to the LED strips I see a black spot on one of the LEDs.

I have access to a bench power supply at work, so I'll take it in to try to confirm.

I see that there are individual LEDs available, but this style looks difficult to work with. Does anyone have any instructions or videos that would help with this?
If I'm unable to do it on my own I will eventually look into buying a whole replacement strip.

[budm]

Re: Samsung UN46ES6100 / no backlight

I would replace the whole set of the strip, one LED already failed so it is better to replace all the strips at once instead of taking panel apart again when other LED's fail.
Then turn down the backlights level to as low as you can on all inputs to extend the life of the LED's.

[Plaxus]

Re: Samsung UN46ES6100 / no backlight

I would replace the whole set of the strip, one LED already failed so it is better to replace all the strips at once instead of taking panel apart again when other LED's fail.

Ok thanks, I can see why that would be a good plan.