Indicator Assembly Pca-A11 And Incandescent; Pack Chamber Assembly Removal And Replacement; Printed Circuit Card Removal And Replacement; Card Cage Pca's - HP 7925D Service Manual

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5-8. INDICATOR ASSEMBLY PCA-A11
AND INCANDESCENT
LA~.~P
REMOVAL AND REPLACEMENT
Removal and Replacement
f. Remove the two screws (66, figure 6-2) that hold the
side plate assembly (65) in place. Remove the side
plate assembly.
To remove indicator assembly PCA-A11 or replace an in-
candescent lamp, 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. Remove the shroud. (Refer to paragraph 5-3,)
d. Remove the front frame assembly. (Refer to
paragraph 5-7.)
e. If an incandescent lamp requires replacement, follow
substeps (1) through (3); otherwise, proceed to step f.
(1)
Being careful not to bend the lamp contact, rotate
the lamp contact on the indicator PCA counter--
clockwise. Remove the defective lamp.
(2) Insert the replacement lamp and rotate the lamp
contact clockwise to hold the new lamp in place.
(3) Proceed to step g.
f. Remove indicator assembly PCA-A11 and replace
with the new indicator assembly.
Note: When replacing indicator assembly
PCA-A11, ensure that the LED on the
indicator assembly is centered in the
hole in the front panel frame.
g. Replace the front frame. (Refer to paragraph 5-7.)
Replace the shroud. (Refer to paragraph 5-3.) Restore
the ac power to the disc drive.
5-9. PACK CHAMBER ASSEMBLY
REMOVAL AND REPLACEMENT
To remove the pack chamber assembly (3, figure 6-1), pro-
ceed as follows:
a. Remove the disc pack.
b. Perform the preparation for service outlined in
paragraph 5-2.
g. At the bottom of the pack chamber assembly, release
the four quick-release fasteners (39 and 41, figure 6-4).
h. Disconnect connector J2 from plug P1 (cable harness
leading to the door lock assembly).
i. Lift the pack chamber assembly out of the disc drive.
To replace the pack chamber assembly, proceed as follows:
a. Loosen (do not remove) the two screws which hold the
preamplifier retainer (44, figure 6-4) and push the re-
tainer upward (toward the door of the pack chamber).
b. Align the four quick-release fasteners over the four
posts on the mainframe and place the pack chamber
assembly on the mainframe.
c. Secure the pack chamber assembly by attaching the
quick-release fasteners to the mainframe and recon-
nect connector J2.
d. Ensure (by visual inspection) that the heads can enter
the pack chamber without interference through the
hole in the side of the pack chamber assembly.
e. Lower the preamplifier retainer (44, figure 6-4) and
push the retainer down on read/write preamplifier
PCA-A6. Tighten the knurled screws (45, figure 6-4).
f. Install the side plate assembly using the two mount-
ing screws.
g. Replace the front frame assembly. (Refer to para-
graph 5-7.) Replace the shroud. (Refer to paragraph
5-3.) Restore the ac power to the disc drive.
h. Attach the 13356A disc pack label (1, figure 6-4) to
the spanner handle (35, figure 6-4).
5-10. PRINTED CIRCUIT CARD
REMOVAL AND REPLACEMENT
Four of the PCA's are mounted in the card cage chassis
and a fifth is mounted in a separate card chassis. The
remainder of the PCA's are mounted in other locations
throughout the disc drive.
c. Disconnect the ac power cord from the ac mains
power.
5-11.
CARD CAGE PCA'S
d. Remove the shroud. (Refer to paragraph 5-3,)
e. Remove the front frame assembly. (Refer to
paragraph 5-7.)
To remove any of the four card cage PCA's, A2 through
A5, proceed as follows:
a. Perform the preparation for service outlined in
paragraph 5-2.