Xerox Phaser 6128MFP Service Manual page 84

Theory of Operation
Low-Voltage Power Supply (LVPS)
Machine Control Unit Board
High-Voltage Power Supply (HVPS)
2-30
Two types of LVPS are available: 100/120V and 230V. The LVPS supplies AC power
from the power source to the Fuser Heater; the LVPS also generates and supplies
stable low-voltage DC power used for the logic circuits. The LVPS contains a control
circuit for the Fuser heater, in addition to the power circuit.
LVPS Over-Current Protection Circuit
This circuit stops all outputs if the power supply voltage 3.3 VDC, 5 VDC, or 24 VDC
is shorted. After short is repaired, cycle main power to reset the circuit.
LVPS Over-Voltage Protection Circuit
This circuit stops all outputs, if the power supply voltage 3.3 VDC, 5 VDC, or 24
VDC exceeds the specified voltage of 32 VDC or less for 24 VDC, 7 VDC or less for 5
VDC, or 4.4 VDC or less for 3.3 VDC. The circuit resets when main power is cycled
after certain period of time.
Deep Sleep Mode (Power Saver)
The output of the following power supply are stopped according to the signals.
Signal
Sleep
Deep Sleep
The Machine Control Unit (MCU) Board controls the printing process based on the
communication with the printer Image Processor Board and information from the
Sensors or Switches. Major functions include:
1. Communicates with the Image Processor Board.
2. Receives information from the Sensors or Switches.
3. Controls the Main and Sub-Drive Assemblies.
4. Distributes low-voltage DC power from the LVPS to each component.
5. Controls the Laser Unit.
Note
When replacing an MCU Board, be sure to transfer the contents of NVM from
the old MCU Board to the new MCU Board.
The HVPS provides high-voltage power to the components in the transfer belt and
Imaging Unit to perform charging, development, and primary transfer of the print
process to the BCR, BTR, and Developer.
+3.3 VDC +5 VDC +24 VDC
Off Off On
Off Off Off
Phaser 6128MFP Service Manual