I had the same issue with a Hi-Sense tv. Different brand, I know, but I have a feeling the internals are all made by the same companies.
TV would turn on and display the Hi Sense Roku TV logo, then turn off. Then turn on again, display the logo and turn off (like a computer stuck in a reboot loop)
I opened it up and took some voltage readings, found the high voltage capacitor was storing around 350 volts even when unplugged, so please don't mess with this if you don't know what you're doing.
I know how to safely discharge it, so did that, then plugged the tv back in. Pressing the on button (either on the remote or the physical one on the tv - doesn't matter), the tv came on normally. Once turning it off, and back on it got stuck in the loop again.
This was after having the Hi Sense authorized technicians come out twice (once during the initial warranty period and once again after the warranty period, because I told them they did not fix it the first time.)
Both times they replaced three boards: power, main and display.
This last time I decided it's not likely to be one of those boards having failed three times, so started looking around inside. Unplugged the wifi (never used it anyway), the display board and the backlight wires.
Powered it up and I could tell by the red LED that it was having the same problem (the red light flashes, then stops, then turns off, then starts flashing again. Loop continues)
Finally purchased a replacement IR board on eBay for $9.50 (tiny circuit board inside the plastic bubble under the tv that contains the IR sensor and physical push button)
I had already tested the push button with an ohmmeter and it seemed ok.
Plugging in the new IR board and powering up the tv it came on as normal. Have turned it on and off a few times over the last few hours and no problems.
I believe the problem is solved.
