Needed a new mainboard. Later the owner admitted to tinkering in the service menu so there's that.
Another result from a google on this finds two other ideas.
1. Unplug all connections. Remove power and wait 10 minutes. Only apply power and try again.
2. Another post found the "button board" has failed. That's the buttons on the side of the TV. They unplugged the connection to that and have to use the remote from now on.
You won't get it repaired out of warranty as this model refurb here is 215 at Walmart.
The min shop charge here is 150USD and that's without any parts or repair!
The model number is 40H5B. I checked all buttons and tried menus but I cant do anything while its flashing solid colors (White, Red, Green, Blue, Black, repeat). I did some research and found a button sequence using the remote which didn't seem to work, until I powered it on by hand on the side of the TV . It worked the last 3 days then it started again today, then worked for several minutes (I restored back to default settings), then jumped back to flashing colors, and hasn't went back to picture again.
Its stuck in the color test mode ?
How can I get it to stop or turn it off, to factory reset it ?
Here is a link to a video I recorded and uploaded of the issue