Vizio M370SL white lines, screen freezing
 

I am working on a Vizio model M370SL with LED backlight. After turning the unit on, I get thin horizontal lines across the entire screen and the image freezes and unfreezes by the clock... every 2 seconds.

All the power supply voltages appear correct.
I have removed inspected/cleaned and reseated all connectors. No change!
The two large ribbon connectors go from the main board to the lower edge mounted display board (instead of connecting to a t-con board).

I'm thinking the problem is the main board due to the momentary freezing and lines across both sides of the screen.

Does anyone have any thoughts they would like to share? It certainly would be appreciated.