HP LaserJet 3200 Service Manual - Page 74

Power system on ECU The AC, DC, and high-voltage power supply circuits are all contained within the ECU. AC power distribution The AC power circuitry supplies AC voltage whenever the power cord is connected to the AC power source. AC voltage is distributed to the DC power supply circuitry and to the AC driver circuitry, which controls AC voltage to the fusing assembly's heating element. DC power distribution The DC power distribution circuitry, located on the ECU, distributes +3.3 Vdc, +5 Vdc, and +24 Vdc as follows: l +3.3 Vdc: Formatter Laser/beam detect circuitry ECU l +5 Vdc: Formatter Photosensors ECU Laser/beam detect circuitry l +24 Vdc: Motor Laser scanner motor Document scanner motor Solenoid Formatter l +24VAdc: High voltage power supply Overcurrent/overvoltage There are two overvoltage devices in this printer: l Fuse F101 provides overcurrent protection for the fusing system circuitry. Checking or replacing the fuse requires the removal of the ECU. Fuse F102 (found only on 110V units) provides overcurrent protection to the printer DC power supply circuitry. l In addition, the +24Vdc, +3.3 Vdc, and +5Vdc 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. 72 Chapter 4 - Operational overview EN