65" LG LED TV. Why did operation become intermittent after several hours watching?

The main panels and the main board have gone bad now and are bad it would be more easier and cheaper to buy a new TV than to repair the current one that you have. CRT TV's on the other hand do last longer than the LCD and newer TV"s do.

Did you replace the ribbon cable and check the backlights?

Not the T-con, this would be the power supply board. The LED's are getting intermittent power. I had an Insignia TV that was doing the same thing!

The led driver AND the T-con board are bad. If you could see a picture with the flashlight then the T-con board would be good. It is not. The led driver can be on the main board or the power supply board. You can get these parts from here: TV Parts Universal TV Stands DLP Chips ShopJimmy

The service manual in the troubleshooting section says that is a power board error, I would try that board.

Hi Patrick,

have a close look at your LVDS cable and screen ribbons for signs of failure or heat damage, and you could try to pull a picture from an AV output in various formats to see if it's the screen itself is failing in some way,

regards

George

Power Issues Troubleshooting
*NOTE* LG & Vizio TVs must be plugged in for 5 minutes before it will turn on*
1. Inspect ALL Ribbons and connectors. Any tears or bad connections between boards must be replaced FIRST
2. If you have any of these boards, it should be the first board to be replaced
A) T-Con Board - Video Problems (No Video with standby light on, audio but no video, grainy, distorted, or color problems in screen)
B) X or Y Buffer Board (Plasma TVs only) - Standby light is on but no power
C) Backlight Inverter / LED Driver - No Video with standby light on
3. Main Video Board
- Standby light is on but no power
- Either video or audio does not work (if no T-Con in TV. If audio but no video it is T-Con)
4. Power Board - No power AND standby light does NOT turn on. If standby light is on try other boards above
5. Panel - No power, distorted picture, lines, slow motion, half screen, faded in / out. Panel problems are usually not worth replacing the panel.