Vizio M65-C1 Powers ON, then turns off and back on

Starting issue: screen starting flickering, turned it off and back on then the screen was just black. We had sound but no picture.

The TV failed the flashlight test.

Removed the back and check voltage. All voltages normal except the DIM voltage. Should be 3v but was reading almost no voltage. LED backlights were not coming on. TV powered on and off as expected, standby voltage was present on power supply board and main board.

Purchased a used replacement Main Board. After installation, the LED backlights were now working. The DIM voltage on the power supply board is now reading 3v. When turned on, the VIZIO icon can be seen. However, the menu will not show up when the button is pressed. After 5min or so, a smallish box is visible in the middle of the screen but the picture is jumbled (colored horizontal lines).

Purchased a new replacement T-con board. After installation, the same conditions defined above existed. After about 15min, the TV started to turn itself off and then back on every 30seconds or so. I cannot turn the TV off using the remote of power button. The Power supply board also no longer shows standby voltage, only 5v. Even with the power turned off, the standby voltage reads 5v instead of the normal 3v. When powered on, the TV registers 5v. I checked the LED driver board voltages and they are all steady and seem to be correct.

I swapped back out the Tcon board but the tv just kept doing the same thing, turning itself off and back on.

I’ll add pictures showing the boards I replaced and the power supply board voltages.