Lexmark 4039-1XX, Service Manual

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18
Service Manual
If some voltages are present, but all are not correct, disconnect all
cables except the LVPS from the system board. POR and verify that
the LVPS voltages are correct. Turn the power back off and, one at a
time, reconnect the system board cables, powering on in between
each connection and checking the voltages. The connection which
causes the voltages to be wrong indicates which component is bad.
Repair or replace the failing component or cable as necessary.
Duplex
The duplexer should home — the front shafts should turn and the
input deflector should move — immediately when you install the
duplexer with the printer already powered on, or when you POR the
printer with the duplexer installed. This means the duplexer has
completed its internal tests and is ready to communicate with the
printer.
If the duplexer does not home it is either damaged or is not receiving
+34VDC from the printer.
To check the connection from the printer system board to the duplex
system board, remove the duplex top cover and table cover.
Disconnect the duplex cable from the printer system board. From left
to right (10P: top to bottom), the voltages on the printer system
board connector pins should be 0, +34VDC, 0, +5VDC, 0, and
+5VDC. With the cable connected, these voltages should also be at
duplex system board JP4-1 through JP4-6. If you do not find a cable
or voltage problem, replace the duplex system board.
A 933 error indicates that communication between the printer and
duplexer had been established but has been lost. Check the cable
as above; if the error persists replace the duplex system board.
23 Paper Jams: Examine the paper path in the duplex unit and in
the fuser exit area for paper or other obstructions. Make sure the
duplex unit is positioned correctly on the printer, and that the gear at
the bottom of the duplex unit meshes with the gear on the top of the
paper tray. Check that the paper is fed with no skew or binds from
the duplexer into the metal channel at the right edge of the tray
cover. The tray roller should move the paper forward when the tray
gear is turned, but allow the paper to be pulled by the D-roll when it
picks. Make sure the belt to the duplex DC motor is in place. Make