9.4
Outpu
t
Modu
la
t ion
Verification
Modulation: M
is
calculated
by
the
following formula.
Vmax-Vmin
M(%)
..
)(100
using the value
obtained
in 9.3, a
nd
check
that
the
Vma)(+Vmin
calculated value
is
20%
or less.
_____
_
_____
~~
;:::~:.::i
2=
===Ma
l(imum
Voltage Valve:
Vma)(
-------~----~-
----"""
7%
Average Voltage
Minimum Voltage Valve: Vmax
Fig. 9.1
Modulation
9.5
Radial Alignment Adjustment
Introduction
This
adjustm
ent
Is normally not necessary.
rf
the
mounting screws for
the
stepper motor loosen, Of
if
parts become defective, or it a
wmpatib
i
lity
error occurs, check and readjust
according
to
the
following procedure.
Ste~
(4)
to
(9) 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 disk
ette.
CAUTION
:
Be sure
to
1"lIe
th,
, Ullnm..,t
disk.n,
under
room conditions
tor
20
mi
nutes
b,tor
' ,
dju,'m,nt
.
(2
) Step
to
the
track specified in
the
Radial alignment column of Ta
bl
e 8.1.
(3) Leave
the
oscilloscope
in
the
same condition as mentioned
in
section
9.3
.
•
Cat
s Eye
System
S.
lS
-inch
(4) Check the
out
put
wavef
orms
for sides 0
and
1.
Th
ey
should
appear
as in F
ig.
9.2.
(5) The
two
wave
form
s
shou
ld
app
ear in
the
amp
li
tude
ratio in
th
e R/A
co
lumn
of Table 8.1
or
better
.
(6)
If
the
specified ratio
is
not satisfied, loosen
the
two
mounting screws for
the
stepper motor.
(n
Move the s
tepper
motor
along
the
base
by
hand
until
the
two
waveforms a
ss
ume
approximately
the
same
a
mpl
i·
tude,
and
retigh
ten
t
he
mou
nt
ing screws. (See Fig. 9.2
.)
(8)
Step
the
head
outward
(track 0) a
nd
inward (
tra
ck
40
or
79),
and
confirm
t
hat
the
adjustment
has
been
c
ompleted
.
(9)
After
the
rad
ia
l
adjustment,
be sure
to
con
firm
trac
k
00
sensor adjus
tm
ent
9,8 and
carr
iage li
mi
te
r 9.9.
- 8 -
•
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