MPI 40 Series - Page 79

4.6.3 Track 00 and 43 Sensor Alignment
To align the track 00 and 43 sensors perform the following steps in
the order listed.
A. Apply power to the disk drive and select drive.
B. Verify the radial-track alignment (see paragraph 4. 6 .1).
C. Connect channel A probe to connector JS-12; set oscilloscope
trigger to INTERNAL/AUTO.
D. Loosen the track 00 sensor mounting screw (refer to figure
4-1) and adjust the sensor for the conditions in E. and F.
following.
E. When the carriage is positioned over track 00, the signal at
JS-12 should be at 4.0 volts minimum.
F. Command a step-in to track 03. The signal at JS-12 should
go to 0.5 volts maximum. Repeat several times.
G. Tighten the track 00 sensor mounting screw.
H. Connect channel A probe to connector JS-4.
I. Loosen the track 43 sensor mounting screw (refer to figure
4-1) and adjust the sensor for the conditions in J. and K.
following.
J. When the carriage is positioned over track 43, the signal at
JS-4 should be at 4.0 volts minimum.
K. Command a step-out to track 41. The signal at JS-4 should
go to 0.5 volts maximum. Repeat several times.
L. Tighten the track 43 sensor mounting screw.
4.6.4 Speed Control Adjustment
To adjust the speed control perform the following steps in the
order listed:
A. Apply power to the disk drive and select drive (send MOTOR
ON if not a standard configuration).
B. Insert a diskette and close the door.
C. Turn disk drive on its side and observe the strobe effect of
spindle pulley. If observed with 60 Hz lighting adjust R4
on Spindle Control PCBA for a stable strobe pattern. Note
that a small amount of strobe "creep" is permissible. If
operating in a 50 Hz environment, place probe on TP 8 on
Control Electronics PCBA and adjust R4 for a 167ms. period
between Index pulses.
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