EXP Computer C4077-90960 - Manual (Page 96)

Engine Test Microswitch
The Engine Test Microswitch, located on the DC Controller PCA, is
activated manually through the square access hole at the right rear of the
printer (see Figure 6-4). This switch causes the print engine to perform an
internal self test diagnostic which bypasses the Formatter PCA and then
prints a full page of black parallel lines. This test is useful for
troubleshooting printer problems because it isolates the print engine from
the Formatter PCA. The engine test printout prints from Tray 3 and can be
activated with the Formatter PCA removed. For more information, see
Engine Test in Chapter 7.
Motors
Refer to the General Timing Diagram (Figure 5-22) at the end of this
chapter for specific timing details for the printer motors.
The Main Motor, MT1 is controlled by the DC Controller PCA. The Main
Motor drives the Main Gear Assembly and rotates during the Initial
Rotation period (following power-ON), the Print period, the Last Rotation
Period, or whenever the printer front door is opened and closed.
The Scanner Motor is controlled and monitored by the DC Controller. It
rotates the scanner mirror during the Initial Rotation period and the Print
period.
The Fan Motors are controlled and monitored by the DC Controller PCA.
All four fans operate at full speed during the printing modes. All four fans
turn off in the PowerSave mode after the Fuser cools down.
The drive signal for the Tray 2 and 3 Paper Pick-up Motor, SMT1, is
provided by the DC Controller PCA through the PIU PCA mounted on the
right side of the Paper Input Unit (PIU). When the job instructions call for
paper to be supplied by Tray 2, SMT1 rotates in a forward direction and
drives the Pick-Up roller for Tray 2. When paper is supplied by Tray 3,
SMT1 rotates in the reverse direction and drives the Pick-Up roller
for Tray 3.
5
Functional Overview
Functional Overview 5-11