Xerox Phaser 8400 Service Manual page 183

e.
Turn off printer and wait 30 seconds for power supply capacitors to
discharge.
f. Unplug power cord and remove printer's covers.
g.
Unplug the following electronics module connectors:
Power Control to I/O board (J800)
Power Control right (J400)
Printhead data (J130)
Waveamp signal (J790)
Power Control left (J390)
Y-Axis motor (J280)
h.
This step removes all other circuits so the electronics module can be tested
alone.
i. Plug in power cord and turn on power to the printer.
j.
The PE and PS indicators should flash an error code reporting that the front
panel is missing. If the proper error message is not flashed, replace the
electronics module and retest the printer. If PE and PS indicators flash,
continue with debug.
k. Turn off printer and wait 30 seconds for power supply capacitors to
discharge
l. Unplug the following electronics module connectors:
Power Control to I/O board (J800)
Power Control right (J400)
Printhead data (J130)
Waveamp signal (' J790)
Power Control left (J390)
Y-Axis motor (J280)
This step prevents any faults from the motors, clutches and sensors from
preventing the I/O board and front panel from functioning.
m.
Plug in the I/O board connector ('P' / J800) in the electronics module. This
step adds the I/O board and front panel to the electronics module.
n. Turn on power to the printer.
o.
If the electronics module, I/O board and front panel are working, the error
code 34,001.43 should be displayed on the LCD to indicate the printhead is
disconnected.
p.
If the correct error code is not displayed, replace the front panel and I/O
board and verify the correct error code appears on the LCD. Retest
electronics module, I/O board, front panel combination.
q. If the correct error code is displayed, continue with the next steps of the
procedure.
r.
If no error code is displayed, return the original front panel and I/O board to
the printer, replace the electronics module and then continue with the next
steps of the procedure.
Service Manual 4-63