I removed the mega169p from a Butterfly and replaced it with a mega329p. Everything seems to work okay except the LCD.
I can see only one complete character. It's the second (or maybe third) character. It's faint unless I view it from below. When I do view the display from below I can see a few segments of the other characters also.
I tried adjusting the contrast by running the original Butterfly application. That doesn't help. That will only lessen the contrast and that makes it worse.
I've looked at the data sheets for the 169p, 329, and 329p and I don't see any differences.
I've looked at the migration documents also and found nothing.
I may have damaged something when I removed and replaced the microcontroller, but I don't know what it would be. I did not use hot air. I removed the original chip with ChipQuik.
I doubt the LCD is sensitive to ESD but if it is, the pins would be essentially unconnected while there was no ATmega soldered on the board.
It would surprise me if it was that sensitive. I've taken apart other LCD "sandwiches" that were held together with a metal frame. I inspected each layer, put it back together, and it works as good as new.
The "view from below" thing is not new. I bought a Butterfly a year ago that requires me to view it from below. But when I do, the display is good.
This Butterfly that I did the brain transplant on, had a good LCD display before the transplant. I checked it out before the operation.