Xerox Phaser 790, Service Manual

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10/00
4-150
Phaser 790/DocuColor 2006
ADJ 5.3
Initial Issue Repairs and Adjustments
ADJ 5.3 ADF Height
Purpose
The purpose is to adjust the height of the Counterbalance and ensure reliable ADF Document
Feed.
NOTE: This procedure gives instructions for adjusting the left-side Counterbalance. However,
the same procedure applies to the Counterbalance on the right side.
CAUTION
An excessive ADF gap can cause problems with document skew and document jams. Insuffi-
cient ADF gap can cause imperfect rotation of the Drive Motor when under a load.
Check
WARNING
To avoid personal injury or shock, do not perform repair or adjustment activities with
the power switch on or electrical power applied to the machine.
1. Switch off the machine power and disconnect the machine Power Cord.
2. Using shim-stock, create a 1.4mm shim to use as a thickness gauge.
3. Remove the ADF Rear Cover.
4. Set the Shim in the positions indicated in Figure 1 and close the ADF.
5. Verify that the gap between the Side Guide of the Platen Glass and the frame of the
Transport Assembly is 1.4±0.2mm. (Figure 1)
Figure 1 Verifying the Side Guide Gap
6. If the gap is incorrect, perform an adjustment.
Adjustment
CAUTION
Be sure to loosen the screws on both the left and right-side Counterbalances. The ADF Frame
will warp if attempting to make the adjustment with the Counterbalance screws only loosened
on one side.
1. Open the ADF and loosen the Counterbalance screws in two places each side. (Figure 2)
Figure 2 Loosening the Counterbalance
Side Guide
Shim Frame
Mylar
The gap between the Shim and Mylar is
between 0 and 0.2 mm
Shim
Positions
1
Loosen the screws (4)
(two on each Counterbalance)