IBM System/360 2050 Maintenance Manual page 102

Processing unit
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must be recleaned.
If
a new bit plane is to be in-
stalled, begin installation procedure; however, do
not remove the bit plane from the polyethylene bag
until all preparations have been made for immediate
installation on the equipment.
Cleaning of the bit plane is necessary when a bit
plane is removed and replaced or when the polyethy-
lene bag is accidentally broken.
Caution
IBM-approved nylon or lint-free gloves must be
worn during all phases of bit-plane handling.
To clean the bit plane, proceed as follows:
1.
Clean a flat surface, as large as or larger
than the bit plane with a lint-free cloth well satu-
rated with cleaning fluid (P/N 450608). The surface
must be lint-free.
2. Clean all array hardware associated with the
bit plane to be installed.
3. Place the bit plane, with the Mylar* side up,
on the lint-free surfacP..
4. Clean upper and lower connector tabs with
lint-free cloth that is thoroughly moistened with
circuit cleaner.
5. Fold clean, lint-free cloth into a pad about
3 or 4 inches square and saturate thoroughly with
circuit cleaner.
Caution
Do not apply circuit cleaner directly to the bit
plane.
6. Briskly rub the Mylar side of the bit plane.
~
Best results are obtained by starting at
one edge and rubbing back and forth over the entire
length of the bit plane. If the cloth becomes dry,
reapply the circuit cleaner to the pad only.
7. Allow bit plane to dry.
8. Immediately after cleaning, install bit plane
in its proper location, using the following ROS bit
plane installation procedure.
Note: Carrying the bit plane in a vertical posi-
tion reduces the possibility of further contamination.
ROS Bit Plane Installation
Note: Extreme care must be taken throughout the
following procedure to avoid damage to the bit planes,
sense planes, or connector tabs. Plastic or lint-
free gloves must be worn when handling bit planes.
1. Turn all setscrews counterclockwise until
pressure plates are just flat to the casting. Do not
back screws out past this point.
*
Trademark of E. I. duPont deNemours
&
Co. (Inc.)
2. Clean the bit plane,
if
this has not been done,
in accordance with cleaning procedure.
If
a new
bit plane is being installed, perform steps 2 and 5 of
the cleaning procedure.
3. Carefully place the bit plane over the two
center mounting studs with Mylar dielectric side
toward sense plane. Gently slip the bit plane over
the upper and then the lower alignment pins and
press flat on the small copper lands around upper
hole and lower slot. The upper alignment hole has
a slight press fit and the lower alignment slot pre-
vents any side motion but allows lengthwise motion
so that the bit plane can lie flat on the sense plane.
4. Install the upper and lower drive connectors
with the mounting screws. Do not tighten spring-
loading screws at this time. This procedure ensures
corre9t location of the bit plane while the spider
assembly is being installed and loaded.
5. Install the large-rubber pressure pad by
placing it gently over the two center studs.
6. Holding the rubber pressure pad in position,
place spider assembly over center studs. The holes
in the spider casting are large clearance holes for
the studs.
7. Exerting light upward pressure on the cast-
ing, align upper corner holes with the mating tapped
holes in the vertical bars. Insert and fasten the
four corner hex-head mounting screws. Do not
over-tighten these screws but make sure they are
bottomed. Fasten the two knurled nuts to the center
studs. The knurled nuts are to be bottomed but must
be only finger-tight when this is done.
Caution:
If
the knurled nuts are too tight, bending and fracture
of the casting may result when the spider is loaded.
8. Using the torque wrench, tighten all set-
screws (1 through 12) to 2 inch-pounds in the se-
quence shown in Figure 94. Repeating the sequence,
I
tighten setscrews inpositions 1 through8 and 11-12
to 4. 5 inch-pounds; tighten setscrews in positions
I
9 and 10 to 3. 5 inch-pounds.
9. After completing step 8, check torque in
sequence indicated in Figure 94 to see that all
I
torques for positions 1 through 8 and 11-12 are
within 4. 0 to 5. 0 inch-pounds and that torques for
I
positions 9 and 10 are within 3. 0 to 4. O inch-pounds.
If
torques are not within specifications, re-torque
as described above.
10. Repeat steps Band 9 until set torque speci-
fications are met.
Service Checks, Adjustment and Removal Procedure
(3/71)
101

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