Lexmark 4039 - B/W Laser Printer, Service Manual

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Service Manual
4039-1XX
For handle-mounted sensor: The voltage at sensor card J2-3 (pin 1
is the bottom pin) should be +5VDC, and the voltage at J2-4 should
be (12L) 10 to 14VDC (16L) 22 to 26VDC. If these are incorrect and
the cable has continuity, replace the system board. The voltage
between J2-1 and J2-2 should be +5VDC when the light beam is not
blocked, and near zero when it is blocked (the voltage takes 15 to 25
seconds to change to the low level).
For redrive-mounted sensor: make sure the plastic bails and guide
are in good condition and that they guide the sensor flag out of and
into the sensor as paper passes into the bin. On the sensor, the
voltage from pin 2 to pin 3 (pin 1 is the bottom pin) should change
from 0 to +5VDC as the sensor is blocked and unblocked. Pin 1
should always m5VDC.
Replace the sensor, the sensor card (on machines with latch-
mounted sensor), or the sensor cable as necessary.
Operator Panel Problem
Possible causes: failed LCD or operator panel card, cable or
connector problem, or system board problem.
Replace the operator panel if POR stops with 1½ rows of pels
displayed.
Run the diagnostic tests for the LCD and for the buttons. If only
some buttons or pels work, replace the operator panel.
If the operator panel is blank: check for +5VDC at pin 1 of the in-line
connector under the top cover, and replace the operator panel if the
voltage is good. Check for +5VDC at (10P/10R/12R/12C/12L) J7-1
(16L) J5-1 on the system board and replace the cable if the voltage
is good.
If the voltage at the system board is incorrect, check that the LVPS is
providing the correct voltages and replace the LVPS if its output
voltages are wrong.