Lexmark 4039 - B/W Laser Printer, Service Manual

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Diagnostic Information
21
4039-1XX
If the thermal fuse has blown, the fuser and the fuser wiper will be
damaged. Before replacing the fuser and the fuser wiper, check the
voltage at (10P) J11-16 (10R/12R/12C/12L) J11-3 (16L)J18-16 as
you POR again. It should stay at 0 until the 922 Error is displayed
and then go to +24VDC(10P: +5VDC); if it does not, replace the
system board, the fuser, and the fuser wiper. Next, measure the
voltage to the fuser lamp during a POR; it should be line voltage until
the 922 Error is displayed, if it is not, replace the LVPS, the fuser,
and the fuser wiper.
If the voltage to the fuser lamp is the not the same as the line
voltage, replace the LVPS.
If the lamp, fuser power cable, thermal fuse, thermistor and lamp
voltage are OK, check (10P)J11-16 (10R/12R/12C/12L)J11-3
(16L)J18-16 to see if the system board is sending the correct signal
to the TRIAC. At POR this signal should go to +24VDC(10P +5VDC)
and then immediately drop to 0VDC until the fuser is warm; if it does
not, replace the system board. If the signal is OK, replace the LVPS.
Fuser: 923 Error
Check the connection and continuity of the cable from the fuser exit
sensor board to system board (10P/10R/12R/12C/12L)J19
(16L)J16. Check the thermistor condition and connection.
Check the thermistor resistance at system board (10P/10R/12R/
12C/12L)J19-5 to J19-6 (16L)J16-5 to J16-6. It should be from 100K
Ohms to 260K Ohms when cold; it may be as low as 2.3K Ohms
when hot but increase quickly as the fuser cools.
Honeycomb
(Areas of the page are covered with faint 6 mm circles.)
This print defect is usually caused by the print cartridge. If it is not
the problem, verify that the tab on the transfer roll housing is
touching the contact on the HVPS; the transfer roll housing should
have continuity to ground. Make sure the HVPS ground lead to the
side frame is in place and making good contact.