IBM 727, Руководство по инструкции

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replacing the coil. This cleaning may be done with a piece of IBM card covered with
Scotch E lectrical tape, adhesive-side out.
7. The complete magnet assembly may be positioned on the lower front plate
so that the moving coil does not bind in the cavity. Position it by shifting it in the
oversize holes.
CAUTION: Never rem ove or loosen any screws in the magnet assembly; doing
so would greatly reduce the gap flux density.
15. 8.2 Removal of Moving Pulley
Remove the retaining wire from its position around the moving-pulley fork and
pull it out of the hole in the moving-pulley pivot shaft. The shaft may then be r e ­
moved and the pulley removed from the fork. Replace in reverse order.
15. 8.3 Removal of Moving Pulley Fork Assembly
Remove the pulley as described above. Using a good solid backing to prevent
bending the shaft, drive the two taper pins out of the fork hub. Carefully rem ove the
spring clip from the moving coil link at the rear of the fork assembly. The fork
shaft may then be removed from the rear.
Replace in reverse order, taking care that the moving coil linkage is not bent
when the spring clip is replaced.
1 5 .8 .4 Moving Coil, Forw ard-Reverse Magnet, Stop-Capstan Adjustments
The purpose of the following adjustment procedure is to keep the entire motion
control linkage as symmetrical as possible, in both a forward and reverse status.
The start-stop times in either direction should be as nearly equal as the tolerances
of the system will allow. The adjustments must be made in the following order to in­
sure required results. The first adjustments are made with power off and the tape
unit unloaded.
Positioning the moving coil:
1. Turn the left and right stop capstans so that the low radius is down.
2. Hold both the forward and reverse moving pulleys up in contact with the low
radius of the stop capstans by pulling down on the moving coil pull rod. Position the
moving coil on the pull rod, by loosening the nut and turning the moving coil on the
pull rod, so that the coil does not bottom on the magnet. At this point, check to in­
sure that the magnet assembly is positioned correctly to prevent the pull rod from
striking the core. Check also that the moving coil and its linkages do not bind at any
point in the up-and-down or sideways motion of the moving coil system. Neither the
guide at the top of the pull rod nor the forw ard-reverse magnet armature should
interfere with any motion of the system.
Positioning and adjusting the forw ard-reverse magnet (Figure 7):
1. Remove the forw ard-reverse magnet assembly from the machine. Do this by
removing the link from the stud of the forw ard-reverse magnet armature and then r e ­
moving the holding screws (8), through the lower main plate.
2. Loosen the six lock nuts at (2) and (3) and (9) to give complete freedom to the
armature and magnet coil yoke assem blies.
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