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5.8.1
MOTOR SPEED ADJUSTMENT WITHOUT FREQUENCY COUNTER
This adjustment procedure can be used only where there is fluorescent lighting:
A.
Insert a diskette, energize disk drive, and start motor. Step head
to track 16 and keep head loaded.
B.
Adjust potentiometer R7, on servo control PWB until lines on
spindle pulley appear motionless. For 60 Hertz power, use
outside ring of lines. For 50 Hertz power, use inside ring.
C.
A one percent speed variation is exhibited by the strobe lines
rotating 90
0
in five seconds.
5.8.2
MOTOR SPEED ADJUSTMENT WITH FREQUENCY COUNTER
This adjustment procedure can be used anywhere a frequency counter is available.
A.
Install a soft-sector scratch diskette.
B.
Start motor, load head, and step to track 16.
C.
Connect frequency counter to TP5 (+Index) on main disk drive PWB.
D.
Adjust potentiometer R7, on servo control PWB, for 200
±.
1 milli-
seconds.
5.8.3
READ/WRITE HEAD·LOAD PAD ADJUSTMENT
To adjust the read/write head-load pad, see Figure 5-2 and use the following procedure:
A.
Insert an Alignment Diskette or any diskette with data on
track 34.
B.
Connect oscilloscope to TP1 and TP2 and sync external positive
on TP5 (+Indexl.
C.
Select disk drive and step head carriage to track 34.
D.
Observe Read signal on oscilloscope while rotating read/write
head-load pad CCW in small increments (10 degrees) until maximum
read-back head amplitude is obtained. The amplitude should be
not less than 200 millivolts peak-to-peak.
5-13
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