Samsung UN46D6003 No picture no sound standby light on. The standby light is on and when I turn the tv on i get the Samsung smart logo and then the picture goes black. I can not power the tv off again with the power button. I tried the flash light test and see no image on the screen. I opened the back up and get the backlights to turn on by disconnecting the power control board from the main board. While all boards are connected I get voltage readings of 122V AC at the connection and 116V DC at the bridge rectifier. I have voltage on test points throughout the board and 12.8v going across to the main board. I also have 1V on all test points for the LVDS connection on the T-con board. So I have power to all boards. I also have differing voltage readings at the back light connection on the power control board. I’ve gotten readings of 116V, 132v,166v and 235V but there are no puffy capacitors and no visible damage on either side of that board. It’s cheaper to buy a new tv than to try replacing all the boards. How can I isolate which one board needs to go?

SOURCE: Vizio VT470M no picture, no sound, no backlight. Power supply board looks good all voltages appear correct.

Im having similar problem and with my limited knowledge of lcd tvs and the voltages ALL being good except the pwr on or sw on voltage from the main board to the power supply which tells it to switch everything on Im guessing that something is going wrong on the main board. In the condition where it freezes it (the power on V) which switches everything on i get varied voltages such as 2.5 or 3 or (the normal 5v) and then when nothing powers up (blank screen) i read 0v on pwr on voltage but all my other voltages are corect (24v to inverter, 12 v to main board, 5v, etc.) Im guessing from researching this is that there is in improper voltage somewhere in the main board circuit. I have been unable to find it so i may order another board and post back.

The Knight

• 76851 Answers
• Posted on Jul 08, 2016

SOURCE: Repairing a LED TV

The main power supply regulator section circuit fault. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.
Search the site by type in the "brand name" to your device; in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.

Electro Med Services

• 6694 Answers
• Posted on Jan 02, 2017

SOURCE: LG LED TV. 50LN5700UH. Picture out. It will flash LG Logo on power up then go black. Image is present by flashlight test. Audio is also present. Power LED is also lit.

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.

The Knight

• 76851 Answers
• Posted on Feb 10, 2017

SOURCE: 2nd try see last sentences....lg led 32ln5310 tv, sound but no picture, no backlights, nothing visible on flashlight test, what should I replace? Main board, T-Con Board, Power Supply board or Leds

The main power supply regulator section circuit fault. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.
Search the site by type in the "brand name" to your device; in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.