HP 7942 Service Manual page 131

the mainframe. Ensure also that the cable
connectors disconnected in steps e,
g,
and hare
properly seated in their mating connectors. Check
that the fan is operating properly before returning
the drive to service.
AS-IO. UO-FRA4 (POWER SUPPLY
ASSEMBL Y A4)
To remove power supply assembly UO-FRA4 (42),
proceed as follows:
a. Perform the preparation for service procedure
outlined in paragraph A5-2.
b. Ensure that the power cord is disconnected from
the - AC l.INE connector on the rear panel of
the drive.
c. Remove the top shroud (refer to paragraph
A5-4) and the front panel (refer to paragraph
A5-7).
d. Disconnect connector Pion power cable assemb-
ly WI (38) from connector J 1 on power supply
assembly urO-FRA4 (42).
e. Disconnect the fan (31) cable connector B 1 P 1
from connector J 1 on power supply assembly
UO-FRA4 (42).
f. Disconnect connector P6 on power cable assemb-
ly WI (38) from connector J2 on power supply
assembly UO-FRA4 (42).
g. Remove the two TIS screws (39) which secure
power supply assembly UO-FRA4 (42) to the
mainframe assembly (5 I). .
h. Remove the T 10 screw (40) and spacer (41)
which secure power supply assembly UO-FRA4
(42) to the mainframe assembly (5 I).
i. Carefully slide power supply assembly UO-FRA4
(42) forward and out of the drive.
I
CAUTION
I
Ensure that the two TIS screws
(39), 1'1 0 screw (40), and spacer (41)
removed in steps I and hare
reinstalled. These attaching parts
are
re~tluired
to properly ground the
Backdating Information
7942 and 7946
power supply to the mainframe as-
sembly.
Reinstallation is a reversal of the removal prace-
dure. Check that the cable assembly connectors
disconnected in steps d, e, and f are properly seated
in their mating connectors.
AS-It. UO-FRAt (DISC DRIVE ASSEMBLY AI)
To remove disc drive assembly UO-FRAI (35),
proceed as follows.
Note: The length of the cables connected
to disc drive assembly UO-FRAI al-
Iowa substitute disc drive assembly
to connected into circuit adjacent
to the installed assembly. This per-
mits operation of the assembly in
the drive to be verified before
removing it from the mainframe.
a. Perform the preparation for service procedure
outlined in paragraph A5-2.
b. Ensure that the power cord is disconnected from
the - AC LINE connector on the rear panel of
the drive.
c. Remove the top shroud (refer to paragraph
A5-4) and the front panel (refer to paragraph
A5-7).
d. Disconnect connectors P3 and P4 on ribbon
cable assembly W 3 (37) from connectors J 1 and
J2, respectively, on disc drive assembly
UO-FRAI (35).
e. Disconnect connectors P4 and P 5 on power cable
assembly WI (38) from connectors J 3 and J 4,
respectively, on disc drive assembly UO-FRA 1
(35).
f. Remove the T 1 0 screw (36) which secures disc
drive assembly UO-FRAI (35) to the side of the
- mainframe assembly (51).
g. Remove the two TI0 screws (36) which secure
disc drive assembly UO-FRAI (35) to the front
of the mainframe assembly (51).
h. Remove the two 6-32 hex standoffs (8) and lock
washers (9) which secure the HP-IB connector
A5-5