Samsung UN55ES6100 No Backlight

Model UN55ES6100 UN55ES6100F UN55ES6100FXZC

This TV turned on but had no backlight.  The owner indicated the TV was set to dynamic mode which cranks the backlight level to maximum.

With the TV opened up, visible damage was found on several LEDs on the left strip.  The right strip tested good with an LED tester.  Searching the part number 2012SVS55 7032NNB LEFT76 2D (hidden beneath a covering label) found a similar part with a 3D suffix and a 10 pin connector.  The 2D version uses a 6 pin connector and I wasn’t able to find this version online.  I did have 3D strips salvaged from another TV.  With the 6 pin connector, only 3 pins are used and the entire strip can be lit by applying power across pins 1 or 2 and pin 5.  The strip has 76 LEDs wired as 4 separate banks of 19 LEDs.  Two banks are wired in series and these in turn are wired in parallel giving approximately 114V (38 x 3V) drop across the entire strip.

The 10 pin header had the following pinout

1 – Bank1-
2 – Bank1-
3 – Bank1+
4 – Bank2-
5 – Bank2+
6 – Bank3-
7 – Bank3+
8 – Bank4-
9 – Bank4+
10 – Bank4+

Wires going to the left strip were black (-), black (-) and white (+).  To create a single strip, I shorted pin 3 to pin 4, shorted pin 7 to pin 8 and wired black wire to pin 1, black wire to pin 6 and white wire to pin 10.  If I kept the original cable to the 10 pin LED strip, it would have made wiring easier.

Another option would have been to replace the LEDs themselves but my reflow station was melting them and a hot plate may be needed to replace them.  They are surface mount and appear to be part TS731A (lots of sellers on Aliexpress).

With the TV assembled, I did notice some mistakes I made during reassembly.  I left some finger prints on the clear plastic panel which were visible on the screen if the image was clear and light.  I also had tore edges of the reflector white backing paper behind the plastic panel.  I had taped the torn pieces back up but it created some bright spots on the edge of the screen.

For disassembly instruction on Samsung edge-lit TV’s, see this post.

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