Often acts as an inertial fuse. It is a frequent point of failure and can be difficult to identify as a protective element at first glance. Q501 (2SK2900 Power FET):

guides for the LaserJet 1320. Voltage specifications for the RM1-2316 heating element.

The "brain" of the RM1-2316 relies on inputs from the DC Controller PCA. The schematic inputs generally include: