Hi @robert818 ,
Given the short time that the screen stays on it would be difficult to check if there were still an image there when the screen turned off because of a backlight problem.
Check to see if it is in the backlight circuit.
Disconnect the power from the TV and then remove the back cover and disconnect the cable that runs between the power board and the mainboard.
Reconnect the power to the TV and turn on the TV.
The backlights should come on and stay on.
There will be no picture because the mainboard has been disconnected.
If the backlights are blinking on and off, it may pay to invest in a backlight tester - example only so that it can be determined whether the problem is in the power board or the backlights. If it is in the LED backlight strips then the tester will help to narrow it down to where exactly once access to the LEDs is possible. There are plenty of videos on YouTube that show how to use a TV LED backlight tester.
You could use a DMM to check the voltage at the LED connector on the powerboard but the voltage may just go from normal operating voltage (~80-120V DC) to high voltage (>200V DC) if there is an open circuit in the LED strips. If it goes from operating voltage to <30V DC then it will be the power board. It may be too quick to get a true reading of what is happening on the meter
I’m not quite sure of the exact voltages but the principle will be the same i.e. operating voltage/high voltage - LED strips, operating voltage/low voltage - power board
More likely it will be in the backlights (faulty LED or connection to a strip) but it might be prudent to know this for sure before dismantling the TV to gain access to the LED strips.
if the backlights stay on it could be a mainboard problem
My view is that it is always better to repair if possible and economically viable if only to reduce the amount of e-waste going to landfill.
If you do decide to get a new TV advertise the TV as faulty good for parts to recoup some of the cost towards a new TV.
Working panels especially i.e. not cracked are always in demand as are boards and no doubt it will be snapped up by someone willing to fix it
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
2
11 
388 
1.5crwdns2936485:0crwdne2936485:0 
crwdns2947414:01crwdne2947414:0
Здравствуйте у меня такая же проблема телевизор включается и выключается на 1 сёк, точь в точь как на видео.
Я купил 2 новые платы материнскую и плату питания поставил но ничего не поменялось. В этом случае в чем может быть проблема если ставлю новые платы?
crwdns2934271:0crwdnd2934271:0 ILYA crwdne2934271:0