Tektronix Phaser 840, Service Manual

Page: 77 / 207

66 Phaser 840 and 850 Color Printers
Checking the process motor and drive train
1.
Determine if the process motor runs. If it does not rotate, go to Step 2.
If it does rotate, go to Step 5.
2.
Measure to determine if +40 VDC is being supplied to the motor. If
power is applied, go to Step 3. If it is not, inspect the process motor's
wiring harness. If the harness is functional, then troubleshoot the
power control board and power supply. Refer back to the topic,
“Verifying power supply operation” on page 60.
3. Disconnect the motor's wiring harness. Measure the resistance of the
motor's windings. The expected resistances are listed in Table 5
“Motor and solenoid resistances,” on page 63. If the windings are
opened, shorted or far out of tolerance, replace the motor.
4. If the motor’s winding resistances are within specification, inspect the
wiring harness for nicks, crimps, opens or other problems. If the
harness is functional, then replace the power control board.
5.
Inspect the gear train on the left side of the printer frame; look for
stripped gears, loose or damaged belts, unseated bushings, or broken
teeth. Be sure to inspect the inner teeth on the process-motor gear.
Media skews passing through the paper path
1. Check to see if the media is excessively curled. Curled media can get
mistracked in the paper path.
2.
Examine the paper path; ensure it is clear of obstructions.
3.
Ensure that the pick roller is not visibly dirty so that it picks up a sheet
of media smoothly and evenly.
4.
Check the upper and lower feed rollers. Also make sure that the front
door is properly closed.
5. Check the flexible, white “paper deskew” springs on the inside of the
front cover. Ensure that none are bent, damaged, or missing.
6. The printer should be installed on a flat, level surface.
7. Ensure the pick guide assembly is properly snapped into the front of
the printer frame.