Hi,
I just had the same grey/noisy screen on my FP3. Found this thread. Removed the display for the first time, cleaned the contacts a bit, reassembled the phone and everything is back to normal. My phone is working after 15 minutes of “repairing” (the display was really hard to get off the frame).
Thank you for making this awesome product and thanks to the community for providing help and solutions.
Best regards,
Plak