Xerox Phaser 6280, Service Manual

Page: 359 / 672

Phaser 6280 Color Laser Printer Service Manual 4-71
General Troubleshooting
DC Power Supply Troubleshooting
LVPS Overcurrent Protection Circuit
This circuit stops all outputs if any of the Low Voltage Power Supply voltages
3.3 VDC, 5 VDC, or 24 VDC are shorted.
The circuit is reset when the short is removed, the power is turned Off, and
then On again.
LVPS Overvoltage Protection Circuit
This circuit stops all outputs if the power supply voltage 3.3 VDC, 5 VDC, or
24 VDC exceeds the specified voltage respectively. The operating point is 32
VDC or less for 24 VDC, 7 VDC or less for 5 VDC, or 4.4 VDC for 3.3 VDC.
The circuit is reset when the power is turned Off, and then On again after
certain time.
LVPS
Troubleshooting Reference Table
Applicable Parts Wiring and Plug/Jack Map References
■
LVPS, PL9.1.4
■
Top LV Harness, PL10.1.16
■
“Map 4 - LVPS and MCU Boards” on
page 10-12
■
“DC Power Supply” on page 10-21
Troubleshooting Procedure Table
Step Actions and Questions Yes No
1 1. Perform the AC power supply
troubleshooting procedure (page 4-70).
2. Does the problem persist?
Go to step 2. Complete.
2 1. Turn the AC power switch Off.
2. Is the Fuse on the low-voltage power
supply board open?
Replace the
LVPS
(page 8-80). Go to step 3.
3 1. Disconnect the connectors J501 and
J502 from the LVPS.
2. Turn the AC power Switch On.
3. Verify the DC voltages between the
following pins on the LVPS:
■
P501-1 pin <=> P501-2 pin = +5 V
■
P501-3 pin <=> P501-4 pin = +3.3 V
■
P502-1 pin <=> P501-2 pin = +24 V
Go to step 4. Replace the
LVPS
(page 8-80).