Laser 128 stopped making the start-up beep (nor does its FDD activate) and the screen looks like this: http://vcfed.org/evan/laser/screen.jpg
Swapped its 6502 into my //e. The //e boots fine. So it's not the processor.
Talking to myself here ...
I put it back together. Only one extra screw (seriously).
Now it works.
All I did was remove and reinsert the processor.