Overcurrent/overvoltage There are two overvoltage devices in this product: Fuse F101 provides overcurrent protection for the fusing system circuitry. Fuse F102 provides overcurrent protection to the printer DC power supply circuitry. You can check or replace the fuses by removing the back cover (page 164). In addition, the +24 Vdc and +3.3 Vdc power circuitry contains an overcurrent protection circuit that automatically shuts off the output voltage when an overcurrent condition occurs as a result of a short or an abnormal voltage on the load side. These circuits automatically reset.
High-voltage power distribution The high-voltage power supply applies an overlap of DC and AC voltage to the primary charging roller and the developing roller. This circuit also applies a positive or negative DC voltage to the transfer roller according to the instructions from the engine control unit. This circuit also controls the image density by changing the primary AC voltage and the developing AC bias according to the print density setting. EN Printer functions and operation 89