Tektronix Phaser 840, Quick Reference Manual

Page: 55 / 160

Service Guide
45
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 it
is, 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 39.
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 42. 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 inside of the printer frame; look for
stripped gears 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 clean 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 none are bent, damaged, or missing.
6.
The printer should be installed on a flat, level surface.