Encoder Pca-A10 Removal And Replacement; 5-26. Spindle Bottom Cover - HP 7925D Service Manual

Removal and Replacement
Call or see your nearest Restricted
Article Coordinator or the Re-
stricted Article Coordinator at
Hewlett-Packard Disc Memory Di-
vision (USA phone 208/376-6000) if
you have any questions about how
to declare and label a Restricted
Article.
To remove the spindle assembly (35, figure 6-2), proceed
as follows:
a. Perform the preparation for service outlined
III
paragraph 5-2.
b. Disconnect the ac power cord from the ac mains
power.
c. Remove the shroud. (Refer to paragraph 5-3.)
d. Remove the side panels. (Refer to paragraph 5-4.)
e. Remove the front frame assembly (refer to paragraph
5-7) and then remove the pack chamber assembly
(refer to paragraph 5-9,)
f. On power and motor regulator PCA-A9, release the
1I4-turn fasteners and lower the PCA into its service
position.
I
CAUTION
I
When removing the spindle assembly, do
not attempt to remove the spindle hub.
Damage to the disc drive will occur if
removal of this component is attempted.
g. From the bottom side of the mainframe, remove the
four bolts with lockwashers (36 and 37, figure 6-2)
that secure the spindle assembly to the mainframe.
h. Disconnect the spindle motor wiring connector from
the PMR PCA.
I.
Disconnect encoder PCA-AID cable connector.
j. Lift the spindle assembly straight out from the
mainframe.
I
CAUTION
I
The inner perimeter of the spindle hub
may contain a series of tapped holes,
some of which may contain items which
appear to be setscrews. These items are
balance weights and must not be
touched. If any weight is moved, the
spindle balance will be disturbed and
damage to the disc drive will occur.
5-14
7925
I
CAUTION
I
The spindle assembly is a delicate de-
vice. Follow the removal/packaging in-
structions provided in the shipping
package containing the replacement
spindle assembly.
To replace the spindle assembly, perform the above steps
in the reverse order. Tighten the mounting bolts to 80
inch-pounds. Before replacing the pack chamber assem-
bly, verify the head cam alignment. (Refer to paragraph
5-22.) Measure the absolute filter air pressure as outlined
in paragraph 2-13. Verify data head alignment. (Refer to
Section III, Alignment and Adjustment.)
5-25. ENCODER PCA-A10 REMOVAL
AND REPLACEMENT
To remove encoder peA-AID (4, figure 6-5), proceed as
follows:
a. Perform the preparation for service outlined in
paragraph 5-2.
b. Disconnect the ac power cord from the ac mains
power.
c. Open the front door and remove the front shield (15,
figure 6-1).
d. On encoder PCA-AlD, disconnect the cable connector.
e. On encoder PCA-AlD, remove two screws (5, figure
6-5) and lift off the PCA.
To replace encoder PCA-AlD, perform the above steps in
the reverse order.
To replace encoder peA-AID, perform the above steps
in the reverse order. When installing the two screws
I
removed in step e, tighten them to 12 inch-pounds.
5-26. SPINDLE BOTTOM COVER
To replace the spindle bottom cover (6, figure 6-5), pro-
I
ceed as follows:
a. Perform the preparation for service outlined in para-
graph 5-2.
b. Disconnect the ac power cord from the ac mains
power.
c. Open the front door of the disc drive and remove the
front shield (15, figure 6-1).
Change 1