The ribbon motor circuitry has an overcurrent sensor to detect a motor failure (short). The ribbon motor contains a sensor to detect if the ribbon is bound (not advancing).

1. Manually advance ribbon, replace if bound.
2. If ribbon catches on a printhead pin, replace the ribbon if damaged. If the pin does not retract after ribbon is removed, turn the printer OFF.
   
   If it retracts, replace the associated printhead driver board.
   If it remains extended replace the printhead.