Lexmark T520 - 20ppm 8MB Par USB Pcl6 Ps3 Ppds Service Manual page 102

4520-xxx
Paper size switch not selecting paper size that is selected.
FRU
1 Paper Size Switch
High Capacity Feeder
Option Control Board
24X Paper Jam Check Tray X Message displays when Tray X is
empty. No Tray X Message displays.
FRU
1 High-Capacity Feeder
Option Control Board
2 Elevator Top Optical
Sensor Cable
Elevator Top Optical
Sensor
2-74
Service Manual
Action
Check for continuity between the
common pin (J5-1) and the pin of the
paper size selected.
J5-1 (Black): Common Lead
J5-2 (Blue) B5
J5-3 (Green) Executive
J5-4 (Yellow) A4
J5-5 (Orange) Letter
J5-6 (Red) Legal
J5-7 (Brown) A5
If any position does not measure
continuity when selected, replace
the paper size switch assembly. If
the switch assembly is operating
correctly, replace the high capacity
feeder option control board.
Action
Check the voltages on the board at
J4-1(red) and J4-3 (blue). The
voltages measure approximately
+5 V dc. If incorrect, disconnect J4
from the board and measure the
voltages again. If incorrect, replace
the high capacity feeder option
control board.
Check the continuity of the sensor
cable. If incorrect, replace the cable.
If correct, replace the top optical
sensor assembly.