HP 7942 Service Manual page 129

the index n01tches on .the EPROM's facing toward
the edge of ERAS. See figure 4-8.
AS-6. FRAS (HOC PeA-AS)
To remove HlOC FRA5 (6), proceed as follows:
a. Perform tbe preparation for service procedure-
outlined in paragraph AS-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
AS-4).
d. Remove thle two 6-,32 hex standoffs (8) and lock
washers
(9)
which 'Secure the HP-IB connector
on HDC 1FRA S
(6)
to the rear panel of the
mainframe~
assembly (Sl).
e. Disconnect connectQr P2 on power cable assemb-
ly WI (38) from connector J4 on HDC FRAS (6)
f. Disconnect connector P I on cable assembly W2
(30) from (:onnector J2 on HDC FRAS (6)
g. Slide HDC FRAS (6) forward and out of the
drive.
I
CAUTION
I
Do nOft reinstall HDC FRA S with a
circuit board jumper in place. on the
"DISK. OR TArE" pins at W2 in ad-
dition to the required circuit board
jumpe~r on the IIDISK AND TAPE"
pins at W3. Failure to observe this
p!l."eca
11
tion will result in damage to
HDC FRAS.
ReinstallatioI1l is a reversal of the removal proCe-
dure. Before installin* FRAS, ensure that there is
a circuit boa.rd jumper (7) in place on the two
"DISK AND TAPE" pins at W3 on FRAS. Check
that there
is
no circuit board jumper in place on
the "DISK OR TAPE" pins at W2. Ensure also that
there is
a
cir4~uit boa~
jumper (7) in place on the
two pins at '"
1.
See figure 4- 8 for the locations of
WI, W2, and W3. Iqstall the EPROM kits (3, 4,
and S) as de:scribed
ili
paragraph AS-S. Ensure
also that the cable
a~mblY
connectors disconnec-
ted in steps e and f: are firmly seated in their
mating connectors.
Backdating Information
7942 and 7946
AS-7. FRONT PANEL
Note: When replacing the front panel on
disc/tape drives with serial number
prefix 2 S 1 9 and below it is man-
datory that the top shroud also
be
replaced.
To remove the front panel (22), proceed as follows:
a. Perform the preparation for service procedure
outlined in paragraph AS-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
AS-4).
d. Remove the four T 10 screws (l0) which secure
front panel (22), with LED cable assembly
W4
(12) and cable assembly W S (1
7)
attached, to the
drive. Move the front panel (22) forward away
from the drive.
e. Disconnect connector Pion LED cable assembly
W4
(12) from connector JS on disc drive DOC
UO-FRA2
(49).
f. Disconnect connector P2 on cable assembly W 5
(17) from connector J3 on tape drive DOC
UI-FRA2 (SO).
g. Remove the front panel (22) from the drive.
Reinstallation is a reversal of the removal proce-
dure. Ensure that the cable assembly connectors
disconnected in steps e and f are properly seated in
their mating connectors. Check also that the
LINE- switch operates freely before tightening the
four T 10 screws (10) removed in step d.
AS-S. VI-FRAI (TAPE DRIVE ASSEMBLY AI)
To remove tape drive assembly UI-FRAI (26),
proceed as follows:
a. Perform the preparation for service procedure
outlined in paragraph AS-2.
b. Ensure that the power cord is disconnected from
the - AC LINE connector on the rear panel of
the drive.
AS-3