My latest RSF (roadside find) is a Toshiba Fire TV which should be called a Jumping TV. Built in May 2019.
It seems to behave when the ambient temperature is under 60 degrees. But as it warms up, the image starts jumping.
It does it to both sides of the display so I don't think it's a problem with the display. Thought maybe the processor on the T-Con board was overheating so I added a heat sink but that didn't help.
Anybody have any experience with these? Thanks.

Try some compressed air or a small fan from a computer on the board when it acts up.

My latest RSF (roadside find) is a Toshiba Fire TV which should be called a Jumping TV. Built in May 2019.
It seems to behave when the ambient temperature is under 60 degrees. But as it warms up, the image starts jumping.
It does it to both sides of the display so I don't think it's a problem with the display. Thought maybe the processor on the T-Con board was overheating so I added a heat sink but that didn't help.
Anybody have any experience with these? Thanks.

Good chance it's a bad display. If the display will run with one ribbon (most do but not all), run it one side at a time.

If it runs on one side without jumping but not the other, you can tape off the X drive signals on the ribbons (videos on line how to).

John