Replacements - Tektronix Phaser 440 Service Manual

7
Cleaning and Maintenance

Replacements

7-4 Phaser 440 Color Printer
Gears: Replace gears that show any signs of wear or breakage. Look for these
problems:
Thinned gear teeth.
Bent or missing gear teeth; check especially where a metal gear drives
a plastic gear.
Fractured or cracked gears.
Belts: Inspect the belts for wear. There are four rubber belts in the printer: a belt
from the head motor to the head lift cam, a belt from the drum motor to the
drum pulley, and a belt from the lower eject roller to the upper eject roller. Look
for these problems:
Loose rubber particles below the belts indicate a worn belt.
Missing teeth in the belts.
Cracking or moderate fraying; a small amount of fraying is inevitable,
so look for other signs of wear before replacing the belt.
Clutches: There are two clutches: the paper-pick roller clutch and the alignment
roller clutch. Symptoms of a malfunctioning clutch are the printer not picking
paper from the tray or random skewing of the print. In such cases disassemble
and check inside the suspect clutch for a lack of grease, a broken spring, or worn
gear teeth.
Refer to Section 8 for replacement procedures.
Thermal head: Replace the thermal head after every 10,000 prints if a decline in
print quality warrants it.
Head lift motor: Replace the head lift motor after 20,000 prints
Transfer roll take-up motor: Replace after 20,000 prints
Paper feed motor: Replace the paper feed motor after 20,000 prints.
Drum belt: Replace the drum belt after 20,000 prints.
Torque limiter: Replace the transfer roll torque limiter after 20,000 prints.