UN40H6203AFXZA not turning on

[73buick]

Have this TV in for a client. Plug it in, standby light blinks 3-4 times, thats it. TCon LEDs light up. Oringinally thought it was the main board. Bought one used on ebay, looked sketchy out of the box, real dirty, etc. Plugged it in, standby comes on steady, but just starts blinking after hitting power button. TCon LEDs never come on. Put original main back in and start looking at power board. Okay, so with main board disconnected and LED connected, I get 177VDC on D1+, 0VDC on D2+ and D3+. Unplug LED, same readings. LED connected, 15MOhm on D1+, 0 on D2+ and D3+. Unplug LED, D1+ starts at about 15MOhm and then slowly starts dropping, D2+/D3+ remain at 0. Shouldn't all the D+ pins read the same? Backlights them selves never seem to turn on. I do have 13V on main board pin out.

Bad power board? LED short?

[neilc6]

Re: UN40H6203AFXZA not turning on

Similar model. If your LEDs sre good and not turning on, likely bad PS board.

https://www.badcaps.net/forum/showthread.php?t=70123

[R_J]

Re: UN40H6203AFXZA not turning on

You have an open led string in the panel. The D+ are not connected together, D2+ and D1- are connected together, D3+ and D2- are connected together. so one of the strings are open.

[73buick]

Re: UN40H6203AFXZA not turning on

I just got an LED tester. On this one, if I use the tester directly on the LED plug, would I need to do put the probes on D2+ to D1- and D3+ to D2-? What about D1+, would I do negative probe to ground?

[neilc6]

Re: UN40H6203AFXZA not turning on

If you looked at my other post, the pics show how I used an LED tester to check the voltage on the three strips. The tester should indicate the voltage through the strip as shown in the pic. You can access the strips from the back by disconnecting the plug from the power supply and there should be black/white pairs to each strip. Black is ground and white is positive. The voltage reading should give you an indication if you have a problem or not. You should be getting 39V on top and bottom strips and 36V on the middle strip (one less LED). My other post also provide a voltage reference for a working backlight.

[budm]

Re: UN40H6203AFXZA not turning on

Testing LED stings with LED tester:
1) Remove female LED connector from the power supply board so you can test each LED string connected to the female connector.
2) Testing LED string #1: Put red probe on D1 + (pin1), Black probe on D1 - (pin 5).
3) Testing LED string #2: Put red probe on D2 + (pin 2), Black probe on D2 - (pin 6).
2) Testing LED string #3: Put red probe on D3 + (pin 3), Black probe on D3 - (pin 7).

Based on your reading on post #1, you have open circuit in the string #1 and that is why the D1 + went up over 170V.
The three LED strings are connected in series to form one large string.