Hi all, I recently purchased a gently used Phantom 3 Professional at a pretty fantastic price from a friend via Facebook who is moving up to the Mavic. I saw it fly... photos, videos, everything looked great. Unfortunately, as my friend packed it up for shipping cross-country, he realized he had to remove the prop guards so it would fit in the original box. YOU GUESSED IT: he accidentally put the long prop guard screws back into the arms, not realizing that he was driving the long screws up into the motors. I spent about 7 hours trying every combination of firmware and fix and never got the bird to fly. Motors never started. Just the dreaded "ESC Error" each time I tried. In researching the error, I discovered the many terrible tales of the dreaded prop guard screws, and realized what had happened. The seller is obviously upset with himself that he killed the drone literally seconds before carefully and lovingly packing it for shipping. (This was truly his baby... he even named it.) He immediately refunded my money, and told me to just keep the drone, either for parts or to try to fix if I wanted. I offered to send the drone back so that he could part it out or fix it, but he said he was so upset about it that he didn't have the heart for it. So, my question is, how costly is this repair? It's possible that all four motors have been damaged (they all have the 2 long screws in them) but might it also be possible that only one or more were damaged and that's causing the ESC error? Since I never actually got power to the motors, I'm hoping the ESC is not fried and she might just need a few (maybe 4) new motors. Is that possible? Is this something you would attempt on your own? Do you recommend a shop that handles this? I just called the only shop in my area that advertises drone repair, and wondering if it's worth the $55 for diagnosis. Is there any way to test a suspected motor, aside from just replacing it with a new one? Thoughts?