I have a LG 55ln5700-uh tv. I turned the TV on and had sound but no picture. I used the flashlight test and determined that I have no backlights but have sound. I ordered and replaced the power supply board as a result. However when I powered the TV back up I still have no picture. The flashlight test still shows a picture when I enter the menu function. Can u help me determine what to try next?

The Knight

• 76851 Answers
• Posted on Feb 05, 2015

SOURCE: lg led tv backlight

Fault with its main board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ . In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Jose Ma DM.

• 540 Answers
• Posted on Jul 08, 2015

SOURCE: TV powers on and and there is a backlight but no picture. The power supply board has been replaced but I haver no LG power up and drop down menus... Bad Control Board? My house was hit by lighteni

Hi, checking user manual there's no soft reset option so maybe the main board is faulty too, usually when there's a damage by lighting in power supply this also reaches the main board since they aren't electrically isolated.

SOURCE: When testin a power supply or led board on tv do i test dc or ac with multimeter?

Your power supply board is working if you get audio and imgaes.

You test AC only the AC side of the transformer before the Rectifier Diodes. Everything after the Diodes will be in DC.

did you get to see any spec of backlight as shown in
LCD LED TV Repair No Image Blank Black Screen Flashlight Test How to Fix...

SOURCE: Samsung TV

If you see a picture with the flashlight you can rule out the T-Con board. It's working. So the led driver board is the problem. TV Parts Universal TV Stands DLP Chips ShopJimmy Go here for replacement parts.

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.