Replacing the Nikon D5100 or D3100 SD Memory Card Door
Thanks a lot! I used this guide to repair not the SD card door but the scroll wheel. After taking photos under very light rain it was not responding (in fact it turned briefly to the next value but returned, so I couldn't use it to change aperture, shutter speed, etc. via the scroll wheel). I opened the rear cover and sprayed a little contact cleaner and compressed air right into the scroll wheel and after that the problem was solved. Thanks again!