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9.4 Output Modulation Verification
Modulation: M is calculated by the following formula.
M(%)
=
Vmax -
Vm~n
x 100
using the value obtained in 9.3, and check that the calculated
Vmax + Vmm
value is 20% or less.
.
---------rr-
. . . .
E:;;:::~==
. .
~-::::z---=:---
Maximum vo1tage vaiue: vmax
Average Voltage
Minimum Voltage Value: Vmin
_ _ _ _ _ _ _ _ _ _
___,1---1--1-~
----------~~---
Fig. 9.1 Modulation
9.5 Radial Alignment Adjustment
Introduction
This adjustment is normally not necessary.
If the mounting screws for the stepper motor loosen, or if parts become defective, or if a
compatibility error occurs, check and readjust according to the following procedure.
Steps (4) to (9) below should be performed regardless of the type, CE or DAD alignment diskette
used. Use an alignment diskette suitable to the type of FDD to be adjusted according to table 3.1
(1) Insert an alignment diskette.
CAUTION:
Be sure to leave the alignment diskette under room conditions for 20 minutes before
adjustment.
(2) Step to the track specified in the Radial alignment column of Table 8. 1.
(3) Leave the oscilloscope in the same condition as mentioned in section 9.3.
•
Cats Eye System
(4) Check the output waveforms for sides 0 and 1. They should appear as in Fig. 9.2.
(5) The two waveforms should appear in the amplitude ratio in the RIA column of Table 8.1 or
better.
(6) If the specified ratio is not satisfied, loosen the two mounting screws for the stepper motor.
(7) Move the stepper motor along the base by hand until the two waveforms assume
approximately the same amplitude, and retighten the mounting screws. (See Fig. 9.2.)
(8) Step the head outward (track 0) and inward (track 40 or 79), and confirm that the adjustment
has been completed.
(9) After the radial adjustment, be sure to confirm track 00 sensor adjustment 9.8 and carriage
limiter 9.9.
-8-
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