Disk Speed Transducer - IBM System/32 Introduction And Maintenance Manual

2.2.8 Disk Speed Transducer
Removal
CAUTION
Do not rotate the disk spindle counterclockwise;
head damage can occur.
Note: If the disk enclosure is being replaced, a
new speed transducer is furnished. The disk
speed transducer can, however, be replaced
separately.
1. Turn power off at the operator control
panel. After the power is sequenced down,
turn the mainline power off at the back of
the machine.
2. Lock the actuator with the actuator lock
m
by moving the handle to ON.
3. Remove the belt guard by loosening the
two screws
m
and lifting it off.
4. Loosen the two screws
~
holding the
spindle locking arm, and slide the locking
arm toward the disk spindle.
5.
Turn the motor pulley clockwise until the
stud on the disk spindle sits in the slot in
the locking arm.
6. Tighten the screws on the spindle locking
arm.
7. Lift the motor to release tension on the
belt, and remove the belt
II .
8. Remove the disk speed transducer wires
from DETB1
IJ -
terminal 7 (black wire)
and terminal 8 (white wire).
9.
Remove the disk speed transducer assem-
bly by removing the two screws
m .
Replacement and Adjustment
CAUTION
Be careful not to damage the disk speed trans-
ducer tip during replacement.
1.
2.
3.
4.
5.
6.
Loosen the transducer clamping screw
g
Make sure the tab on the transducer is in
the slot in the bracket.
Replace the transducer assembly with the
two mounting screws
Ii .
Adjust the transducer for a gap of 0.006
inch
±
0.002 inch (0.1524 mm
±
0.051
mm)
m.
Note: The transducer assembly might have
to be adjusted to obtain the correct gap
between the transducer and the spindle
pulley.
Tighten the transducer clamping screw.
Connect the transducer cable to DETB 1
II
terminal 7 (black wire) and terminal 8
(white wire).
Install the safety cover on DETB1 (holes to
the left).
m
7. CAUTION
Make sure the belt does not contact the
disk speed transducer.
Replace the belt (smooth side of the belt
against the pulleys). Center the belt on
the pulleys.
8. Loosen the two screws
iii
holding the
spindle locking arm, and slide the locking
arm away from the disk spindle.
9. Make sure the antistatic brush is contacting
the center of the spindle.
Note: If there is a wear crater on the spin-
dle antistatic brush, realign the crater to
the spindle.
10. Tighten the screws on the locking arm.
11. Check that the antistatic brush has a pres-
sure of 60
+
25 - 20 grams on the center
of the spindle. Adjust, if necessary, by
removing and forming the brush.
12. Install the belt guard
CI .
Slide the belt
guard all the way to the left and tighten
the screws.
13. Unlock the actuator lock
m
by moving
the handle to OFF.
m
Disk Drive 2-21