Samsung LED TV UN50J5200AFXZA, screen flashes white light

Samsung UN50J5200AFXZA

Both the screen flashes white and the standby light clicks on and off as soon as I plug the TV in. So far I've tried:

- putting in a new power board

- putting in a new main board

- unplug the main board from the power board, same result

Now, when I do these tests and check voltages on the power board, my multimeter bounces around. Finally I tried unhooking the LEDs themselves from the power board and then checking voltages. They're stable. So my question is:

Have I limited the problem to the LED strips? I should just replace them?