How do you fix an xacto 167x pencil sharpener that stopped working after being dropped?

The shaving tray is likely broken. Pull the tray. Look at the face fits up against the pencil sharpener. Is there a 3/8" diameter rough circle about in the middle of that face? If so there used to be a rod attached at that point. You either need to disable the shaving tray placement interlock or find something smooth to replace the 1.5 inch long rod that broke off.

We used a bit of brake line tubing. My husband tapped one end to accept a small bolt. He drilled out the rough hole on the tray. He put the bolt through the hole in the tray and screwed the brake line tubing piece on to the bolt. (If you try to go with a 3/8" bolt instead of smooth tubing - you won't be able to take the tray out again. Hope this helps.