white screen

forgive me if this was asked already but i didn't see anything.

couple mornings now when I turned on the box the picture was like a big shadow and really hard to make out, the first time I restarted a couple times and it corrected it self. today it would not , I did notice when I held the power button and the side menu for shutdown, restart popped up it went away but as soon as i exited it went back to a bad picture quality , should I reset and start over? I will change the HDMI cable when I get home but i don't think thats the issue.

thanks

HDMI cable first. I have my second 4900 and recently it was acting funny. I'd power it up, but I would get no picture at all sometimes. After about 2 minutes, I'd unplug the HDMI cable and plug it back in, and all was good.

Finally got around to running a new cable (procrastinated, since it is a tight squeeze between the wall the back of TV), and problem so far seems to be fixed. So something was marginal on the cable. And marginal cables act funny sometimes depending on ambient temperatures.

Must be the tv I changed cables and ports and nothing so I unplugged the tv and it is working so we will see