6 • Service Menus
PM Diagnostics (cont'd)
The sensor diagnostics option shows you the state of the machine sensors
(see table on the previous page for a list). You can test a sensor by manu-
ally changing it's state and confirming the change on the display screen.
(P)S1, (P) S2 and (P) S3.
These are the mailing ma-
chine's transport sensors as
shown in the accompanying
figure. When you block the
sensors with an envelope or
piece of paper, the display
should change from Clear to
Blocked. If all three sensors
work properly, it is likely that
the sensors, sensor junction
board and cable to J119 on
the Main Logic Board are
okay. If all sensors fail, there
may be a problem with the
sensor junction board, the cable to J119 or the main logic board. If the dis-
play shows a blocked sensor that should be clear, try cleaning the sensor.
NOTE: The 6C00 does not have a PS2 on its sensor board, but it is still
listed in Diagnostics and it will always show as "Clear".
Jam Lever and Top Cover Open. These are the machine safety interlocks.
The system will not operate if the top cover is open or the jam clearance
lever is unlocked. To exercise the sensors, open and close the top cover
and unlock the jam clearance lever. If a sensor fails to change state, the
problem could be a mechanical problem affecting the sensor flag, a mis-
alignment, or a wiring problem. For the top cover interlock, check the wiring
to J121. For the jam clearance lever, check the wiring from the sensor junc-
tion board at J119.
Cap Home Position. Cap should be in Cap Spit position.
Pump Home Position. Pump should be in Home Position.
Carriage Position. Indicates location of print carriage. In the capped posi-
tion, the carriage is home and the carriage position sensor is blocked.
Print Head Vol(tage). Should be ON (except when a cover is open or ma-
chine is in sleep mode).
Figure 4-5 Transport Sensors (3C00, 4C00,
DM300c/DM400c/DM475 Service Manual (SV61801 Rev. D)