I have a LG 50LN5600 LED Smart TV w/sound no/pic Have replaced the power supply board and t-con board. Main board only one left and research says that this would not be a main board prob. Any help?

The T-Con board is embedded in the main board and not in the power supply/LED Driver board.
The Main board part number should be BN94-09124C but I would suggest to do more research or call Samsung for more info.

did you change power supply? how many times does light flash (red) you didnt change the power supply did you use a vom on connections?

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hi the led or leds has shorted in the panel, thanks

shaun

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Hello Dararius,
When you shine the flashlight at or near the screen and see the images, it means that the LEDS located behind the screen are not working. Since LED's don't usually blow out, it means that the LED driver circuitry located on a pc board inside the set is blown out and either needs to be repaired or just buy a new pc board from ebay such as the following:
http://www.ebay.com/itm/LG-EBT62679606-EAX64872104-1-0-Main-Board-for-50LN5600-UI-/361039485726?hash=item540fa15b1e:g:MBcAAOSwSdZWe5E0

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electro-medical.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Hi Tom,
It appears to be a back light failure. Please see that the back lights are receiving the power they need.
Good Luck.

Check whether the back-light start voltage [control voltage] comes to the backlight inverter section of the power board; from the main board. It sounds that that voltage does not come from the main board, after the firmware has been loaded up. If so the main board will have the fault. Contact any service technician.

I'd try the main, its about all that is left if the rails are all good on the power board.