The more I think about this, the more I come back to a poor connection. The connection is making or breaking under changes in temperature.
That's what led me down this road in the first place, so my sentiments exactly LOL.
from what I can tell, all of the display works either correctly, or not at all. This means that it is most likely to be something common to the whole display.
Again, exactly what I was thinking....
common to everything is...... the earth!!
I think the power is also made prime suspect by the fact that the display resets every time.
Great minds and all that
So this brings us back to the same question, is it the display, or what feeds it.
I have some suspects, namely a little blue component on the seperate smaller board, semi-encased by a large metal shield type thing (not sure of its' function), a partially broken wire as you say.
The best you could hope for without circuit diagrams and test gear would be to closely examine every solder joint and re-flow any that look suspect, you may just get lucky
Done that, did find a few and sorted them very carefully to no avail.
I really wish you luck with it and it sounds like you relish a challenge, but you may have to concede that this one will beat you.
Tell me about it LOL.
Anyway, I'm not quite done with it yet, a few more things to try, after that it's off to the repair shop. If it isn't sorted after that then I don't know what I'm going to do with it as I can't afford new BII or display, far too much money.....leaves me in a sh*tty situation indeed.