Minolta CF910 Service Manual page 446

<Troubleshooting Procedure>
Step
11 Are the PH Upper and Lower Units incor-
rectly installed? Is the PH Lower Unit win-
dow dirty?
Check Item
T-79
Result
NO Change the Polygon Motor
Drive Board, PWB-JA, and -JD,
and PH Upper and Lower Units
as a set. ("IR Area," "PRT
Area," and "Gradation Adjust")
If the replacement units are not
readily available:
• Temporarily adjust "VB Shift."
(The value should be reset to
"0" after the units have been
changed.)
YES Reinstall or clean the units.
("Gradation Adjust")
Action