原帖由： wayne wayo aveyard ,
This sounds like an alignment problem. it is more than likely that when dropped the mechanism has shifted and under the pressure of the already tightened screws it has stayed misaligned. i would suggest opening it up carefully following a guide on youtube. just take all the parts out clean them up/check if any are broken or cracked (you may have to use a little bit of thumb pressure to check certain parts for cracks) and if all is good just put it back together again carefully lined up. wd40 is good for cleaning non electric parts due to its water displacement and lubrication qualities.