UE40D5520 switching on and off and not functioning normally

[artia]

I bought this UE40D5520 TV in 2011 and it has worked well for years. A few years ago, when I switched it on, it would display the Samsung TV logo, then go dark, then switch off, and this would repeat on loop. I thought about buying a new TV and when I tried turning it on a few days later it was working and back to normal. Since then it worked fine for two more years. 

A few days ago the same thing happened and it is switching on and off on a loop. If the power remains plugged in there is no way to switch it off either with the remote or with the switch on the frame of the TV. I have to unplug it altogether.

Any ideas if there is anything that can be done? The LED screen seems to be fine because the log appears, but it is something with it turning on and staying on that is the problem. Any ideas?

I have had a good TV that has lasted 14 years so I would be ready to buy a new one. But don't want to ditch it before trying one more resuscitation...

[JAMES4578]

Hi @artia  Welcome to the Samsung community  

Actually I think the TV has likely reaching the end of its life and obviously repair would not be viable. sometimes boot loops can be caused by outdated software but there has not been update for a while https://www.samsung.com/uk/support/model/UE40D5520RKXXU/

However a few things you could try: 

check connections are secure, could try  switching tv off at mains  and reconnecting  external cables  before powering on to see if that makes any difference.

By any chance are you using a Power surge, if you have a green light on the surge part should be ok.  However if so try plugging directly into a socket to rule that out.  Are you getting a standby light at all, if no red light present that does indicate a fault. can check  troubleshooting with various lights here https://www.samsung.com/us/support/troubleshooting/TSG01001086/#tv-s-red-standby-light-is-off   

Another possible fix though is to hold the Power Button on the Remote for 30 seconds till it hopefully Reboots,unplug from mains for 1 minute and try again.