The screen is shaking horizontally. It does this

42H83 is a Toshiba first made in 2003.

What is wrong (98% chance) is the HYPER BOARD in this set is now failing----all signal from all inputs is processed thru this board.

Considering the board is now only available on a rebuild basis----and the cost for this is well over 200 dollars not counting labor to remove--replace--set, unless you know someone who is VERY GOOD AT SOLDERING-----not worth repairing.

What happens here is this board has close to 20 surface mounted filter caps---with time and heat they dry out---usually the time before the problem clears up will get longer and longer---leaking caps may start to function to some degree after they get hot--hence the time from dead cold until the set works.

Most caps have 2 leads and are soldered through the circuit board----these are very small caps with tabs on them----and are soldered to the top of the board.

I am sorry to give you not so good news--but based on your description---I am sure it is your problem.

Call around your area telling them model number and you suspect it is a bad HYPER board---if a shop can actually fix it(replace the caps) parts cost would be under 30 dollars---

Any authorized Toshiba repair shop can go online and see the service bulletin for this--they have a large color picture of the board and indicate which caps have to be replaced.

If this information helped you, rate this solution as I do this here for free.

If you have questions or want advice let me know--I am here to help people.

SD TECH