1. Never loosen the screws that secure the LD drive board to the laser diode casing. This will put the LD unit out of adjustment.
  2. Never attempt to adjust the variable resistors on the LD unit. They are pre-adjusted at the factory.
  3. The polygon mirror and F-theta lenses are very sensitive to dust. Never open the optical housing unit.
  4. Never the glass surface of the polygon mirror motor unit with bare hands.
  5. After replacing the LD unit, do the laser beam pitch adjustment. Otherwise, an SC condition will be generated.