W820 (4025-xxx)

4025-XXXComponents attached to or associated with the MCU PWB:1. I/O PWBInterface between the MCU PWB and most of the printer components.2. Low Voltage Power SupplyConverts AC line voltage to +5VDC and +24VDC.3. ESS PWBConnected to the MCU PWB. The interface between the print engine and the hostcomputer. The ESS processes the raw video data sent by the host computer.4. Control PanelConnected to the MCU PWB, the Control Panel displays status information sent fromthe MCU PWB and ESS PWB.5. AC Driver PWBSwitches 110VAC to the two Fuser Heat Lamps. Fuser temperature sensors areconnected to the AC Drive PWB. The AC Drive PWB sends the temperatureinformation to the I/O PWB, which sends the information along to the MCU PWB.6. High Voltage Power SupplyConverts +24VDC received from the I/O PWB to several high voltages that arerequired by printer xerographics.7. PSHV-R2Converts +24VDC received from the I/O PWB to the Fuser bias voltage.8. Toner SensorMagnetic sensor that monitors the CRU toner level.9. CRUDrum usage information that is stored in the CRU.10. PrintheadThe SOS (Start of Scan) Sensor, the Printhead Motor, and the Laser Diode.11. Main MotorProvides most of the mechanical drive for the printer.12. Drum MotorProvides drive for the CRU.13. Fuser FanCools the Fuser area.14. Feed ClutchTransmits Main Motor drive to the Tray 1 Feed Rolls.15. Registration Gate ClutchTransmits Main Motor drive to the Registration Rolls.1-18 Service Manual