Sounds like main board. Since it works after warmup the usual test a TV tech would do is warm up the mainboard with a heat gun then power up to confirm that's it.
If you don't do electronics repair then you may be stuck with your best guess.
https://www.electro-tech-online.com/threads/freezing-or-heating-up-components-transistors-and-fets-etc-for-troubleshooting.139250/ if you are new to this area.
My 55 inch Vizio is having struggles. I can get it to work after 10-40 minutes of what we now call "warm up time".
When we power on it often has major horizontal blurring. Think of like when you tried to get the late night HBO soft core show, but your parents didn't subscribe to HBO. It's sort of like that but even more messed up. All the colors are there but it's just a mess. After some warm up time it improves and eventually the picture is back to normal.
I've already got a new tv on order arriving Wednesday but this one works enough where I'd like to try and fix it and move to the basement for the kids.
Anyone have any idea what I might look at to fix it? Main board? Some other board?
Thanks!
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