Xerox 4400DT - Phaser B/W Laser Printer Service Manual page 103

DC Power Loading
Note: Perform
Warning: AC input voltages can be lethal. Use extreme caution while
checking the voltages on the LVPS. Disconnect the power
cord while checking the continuity of fuses and while
removing or reinstalling components.
DC Power Loading Troubleshooting Procedure
Step Actions and Questions
1 1. Switch the printer power OFF.
2. Remove the Left Interface Cover (RRP 1.1 on
page 6-6), Left Cover (RRP 1.2 on
Left Plate (RRP 1.11 on
3. Disconnect the following from the LVPS:
P/J281 (Engine Logic Board)
I
P/J282 (Image Processor Board)
I
P/J283 (LVPS Fan)
I
Pn1 (5 VDC Power Supply)
I
4. Go on to step 2.
2 1. Switch printer power ON.
2. Measure the voltage between P/J281 pin 7, and
frame ground. It should be +5.0 VDC.
3. Measure the voltage between P/J281 pin 10, and
frame ground. It should be +3.3 VDC.
4. Measure the voltage between P/J281 pin 1, and
frame ground. It should be +24.0 VDC.
Are all the voltages correct?
3 1. Switch the printer power OFF.
2. Reconnect P/J281 to the LVPS.
3. Switch the printer power ON and measure the
voltages listed in Step 2, sub-steps 2 through 4.
Are all the voltages correct?
4 1. Switch the printer power OFF.
2. Reconnect all the P/Js to the LVPS.
3. Disconnect the following from the Engine Logic
Board:
P/J22 (Laser)
I
P/J21 (Laser, SOS)
I
P/J23 (Connector PWB)
I
P/J25 (Print Cartridge Sensor)
I
P/J32 (Exit Motor)
I
P29 (Main Motor)
I
P/J26 (HVPS PWB)
I
P/J27 (Exit Sensor)
I
P/J31 (Stack Full Sensor)
I
P/J33 (Size 1 PWB)
I
P/J34 (Duplex PWB)
I
P/J35 (Stacker PWB)
I
4. Switch the printer power ON and measure the
voltages listed in Step 2, sub-steps 2 through 4.
Are all the voltages correct?
3-6
"DC Power (LVPS)"
page 6-16).
before starting this procedure.
page 6-7), and the
Phaser 4400 Laser Printer Service Manual
Yes No
Go to step 3. Replace the
LVPS (RRP
9.5 on
page
Go to step 9. Go to step 4.
Go to step 5. Replace the
Engine Logic
Board (RRP
9.3 on
page
6-91).
6-89).