Tektronix Phaser 840, Service Manual

Page: 109 / 207

98 Phaser 840 and 850 Color Printers
Y-axis belts tension adjustment (Phaser 840 printer)
Perform this procedure after loosening or removing the Y-axis belt drive
assembly. Note the additional steps you must perform for a new Y-axis drive
assembly.
1.
Ensure that the three mounting screws that secure the Y-axis drive
assembly to the chassis are 1 turn loose and that the Y-axis idler bracket
slides freely with respect to the chassis.
Note
If there is a situation in which diagnostics are not available when
installing a new Y-axis drive assembly or drum/transfix assembly,
then locate any previously placed index marks on the pulleys and
proceed as if re-using existing parts. Allow the system to cool as
long as feasible before mounting the Y-axis drive assembly onto
the chassis. Tensioning of the y-axis drive assembly without
diagnostics increases the risk of failures associated with low belt
tension (for example, a “growling” sound heard upon cold power-
ups).
2.
Attach the Y-axis belt tension tool (in its unloaded or folded out
position) to the keyholes in the side frame of the printer just below and
in front of the Y-axis drive assembly. The tool's fishhook should engage
the eyelet of the Y-axis drive assembly.
3.
Pull forward and down on the lever arm of the tension tool to apply
tension to the Y-axis belts.
4.
While the belts are under tension, rotate the drum pulley 5 times to
rotate the belts and seat them in place. For an old Y-axis drive assembly,
continue rotating the pulleys until the index marks on each pulley align
next to each other.
5.
Beginning with the upper-right screw, tighten the three mounting
screws to 30 in.-lbs. to secure the Y-axis drive assembly in place.
6.
For new Y-axis drive assembly. Using PC-based diagnostics, run the
test: “Position for Belt Tightening” in the “Y-Axis Group” test suite.
This positions the belts in the proper orientation for re-tensioning. Do
not move the pulleys.
7.
Place an index mark on the edge of each pulley: Mark the Y-axis drive
pulley and the drum pulley where the edges are closest to one another,
disregarding previous marks. Use a distinct color if the pulleys have
been previously marked.
8.
Loosen the 3 mounting screws until the bracket slides freely on the
chassis and then re-tighten the screws to 30 in.-lbs.
9.
Release the tension tool's lever arm and remove the tool.