Xerox 4400DT - Phaser B/W Laser Printer Service Manual page 101

DC Power (LVPS)
This procedure is used to troubleshoot the Low-Voltage Power Supply.
Note: Perform the AC Power checks before starting this procedure.
.
DC (LVPS) Troubleshooting Procedure
Step Actions and Questions
1. Switch printer power OFF.
1
2. Disconnect the power cord.
3. Remove the Left Interface Cover (RRP 1.1 on
page 6-6), Left Cover (RRP 1.2 on
Left Plate (RRP 1.11 on
4. Connect printer power.
5. Switch the printer power ON.
6. Measure the voltage on the LVPS between P/J285
pins 1 and 2.
Does the voltage match the line voltage?
1. On the Low Voltage Power Supply, measure the
2
voltage between both sides of the Fuse F1 and frame
ground.
Do both readings match the line voltage?
3 1. Switch the printer power OFF.
2. Replace fuse F1 (125 V - 10 A / 250 V - 3 A).
3. Switch the printer power ON.
4. Measure the voltage between both sides of the Fuse
F1 and frame ground.
Do both readings match the line voltage?
1. Measure the voltage between LVPS P/J281 pin 1 and
4
frame ground.
Is the voltage +24 VDC?
5 1. On the LVPS, measure the voltage between P/J284
pin 2 and frame ground.
Is the voltage +24 VDC?
6 1. Switch the printer power OFF.
2. Disconnect printer power.
3. Disconnect P/J 281.
4. Connect printer power.
5. Switch the printer power ON.
6. Measure the voltage between LVPS P/J 281 pin 1 and
frame ground.
Is the voltage +24 VDC?
7 Measure the voltage between P/J 284 pin 1 and frame
ground.
Is the voltage +24 VDC?
3-4
page 6-7), and the
page 6-16).
Phaser 4400 Laser Printer Service Manual
Yes No
Go to step 2. Replace the
AC Power
Cord.
Go to step 4. Go to step 3.
Problem Replace the
solved. LVPS (RRP
9.5,
page
Go to step 9. Go to step 5.
Go to step 7. Go to step 6.
Go to "DC Replace the
Power LVPS (RRP
Loading". 9.5,
page
Replace the Go to step 8.
LVPS (RRP
9.5,
page 6-91).
6-91).
6-91).