Solved! What controls the backlight on/off on an LED television? Need a technical question answered!

[wgrace07]

I don't know that this is the appropriate place to ask but if anyone can answer my question it would be greatly appreciated--I don't know if I should junk this TV or not.

I have a 60 inch Samsung LED smart TV. The model number is UN60J6200AF. It has no picture, but sound, and the flashlight test reveals a working image. This model is known for LED strip failure but this is not the case if my testing is correct.

At first I suspected the power board. It has four wires going to the LED panel configured as 1-Ground-Ground-2. Power wire #2 has 450 volts, #1 has 0 volts.

When a wire is bridged from #2 to #1, the LED panel illuminates and the TV and backlight are completely functional? I replaced the power board thinking it was the problem, but it did not fix it.

The other visible boards in the television are a main board with the video connections and a T-Con board below. I do not see a separate backlight inverter or LED driver. Are either of these components primarily responsible for switching the backlight on/off? There is no visible damage to either of them.

 

[jsmithepa]

I have no idea what exactly power the new LEDs, and if u are lucky sometimes there is outward hint but other times u just don't know until u put some kind of meter measuring device on it.

 

[wgrace07]

I have no idea what exactly power the new LEDs, and if u are lucky sometimes there is outward hint but other times u just don't know until u put some kind of meter measuring device on it.

I'm thinking that it's broken down like this. Power wire #1 and ground are for the LEDs, and #2 and ground are for the panel since the display works fine. There doesn't appear to be a separate driver for panel/LEDs and it's all integrated into the power board. When you bridge them you're siphoning display power over to the LED strips. I don't know. I am wondering if the main video board has to supply the signal to the power board in order to switch the backlighting on and it is just not sending the signal.

 

[wgrace07]

For anyone that comes across this same issue--I found my own answer after searching for voltage readings on the power board. The main and only connection from the video board/main board sends a 5v signal to the power board through connector CNM803. Without proper voltage from this connector the power board will not supply power to the LED strips.

https/www.pcrichard.com/images/promos/12Samsung%20CE%20Newsletter%20Dec%202012.pdf