if not the cable, then the proximity sensor. i've seen it catch a media guide and get torn off. you can see the sensor from the back side of the printer, looking through the paper path. it's attached to the cut carriage, usually a white plastic connector. looks like the emitter on the end of a remote control.
less obvious, there are 3 cables that plug into the cut carriage board, crop mark, cut power and prox sensor, maybe the connection got loose?