My LG LED TV (42LN5700) keeps turning itself off and on.I tried unplugging and letting it sit, to see if this would reset anything. The problem persisted. Is there anything else I can try?

Check the backlight power/driver board. Also check the voltages on the main power board.

Hi,
Try try to update the firmware of the tv. Sometimes errors in the firmware can cause such problems. Here we have added the link to the software update for your tv offered by LG and also the user manual.Before trying to update the tv try to read the manual thoroughly, how to update the firmware.

Product Support

If you have the tv and it is intact then refitting is a reversal of removal. Make sure it is unplugged and switched off. I would take anti static precautions even though it is a high voltage component.
You could always video the deconstruction and labe all the parts with masking tape oe something.

Good Luck it you take the task on, you can always have a technician do it for you if you decide against it.....but that is no fun!!!

I'd try the reset first. You could try asking their support. They seem to answer every question that they are asked, and the answers seem pretty thorough.
Product Support

42LN5300 is not a smart TV, you need 42LN5700 and up

Hi there
Try doing a system reset on the TV, by unplugging everything from it, then wait 3 minutes and plug the power lead in only. If it works, then plug everything back in one by one. If the problem persists it may be that the software has been corrupted in an update process, which can be performed at night via the aerial signal (this may be why it was turning on at night). In which case contact the TV manufacturer.
Hope this helps
TV_Doctor

the software in the main control is damaged. call your lg servicer in your area. he might get you a software update

The power light is an error code that tells me exactly what is wrong with the TV. Count how many times the POWER led flashes per second? (Dont worry about the OPC led)

1x per second (constant steady blink) = bad inverters/lamps
2x per second = bad power supply
3x per second = bad main board

If its 1x per second, try doing the factory initialization to get the TV back on to confirm a bad lamp/inverter.

Try doing the Factory Initialization (WARNING: THIS GIVES YOU ACCESS TO THE SERVICE MENU. DO NOT ADJUST ANYTHING IN THE SERVICE MENU OTHER THAN WHAT I PROVIDE YOU IN THESE INSTRUCTIONS. IF YOU DECIDED TO ADJUST ANYTHING OTHER THAN WHAT I PROVIDE YOU IN THESE INSTRUCTIONS, I WILL NOT BE RESPONSIBLE IF ANYTHING WRONG HAPPENS TO YOUR TV.)

1. unplug tv
2. press and hold at the same time “Vol –“ and “input” button on the TV set.
3. while holding those buttons, plug the tv back in
4. the tv should turn on by itself, keep holding the buttons until the letter “K” appears. Then let go.

Once the TV turns on, take a look at the screen. Does it flicker then shut off? Or do you hear a buzzing noise from the right edge of the TV? If so, then you have bad inverters or lamps. Once youre done, unplug the tv to get it out of the service menu.

If it is 2x per second or 3x per second, then those boards are just bad and they need to be replaced. There isnt anything you can do right now to fix it.

Found that TV started switching off by itself. Would try to come on..green light blinked for 2-3 seconds, tv came on (with picture and sound) for 1 or 2 seconds and then it would turn itself off. Found that the issue is with one channel only. If you are facing this issue....try quickly changing the channel the moment it comes on. You can do it either with remote or with the TV buttons directly. also in the same logic, if this is still happening, try changing the source to another (rgb-pc, av1, av2 etc). Basically change it from whatever input it is on currently, if changing the channels does not work. My symptom was that the tv made a loud 'TIK' 'TAK' sound which is louder than normal.