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(5)
(6)
(7)
(8)
(9)
(10)
FDD412A/B
The
rotational
speed
of
the
spindle
motor
is
360
rpm.
Head
load
solenoid
By sensing
the
presence
and
absence
of
the
HEAD
ENGAGE-N
signal
from
the
controller,
the
head
load
solenoid
engages
the magnetic
head
(to enable
reading/writing)
and
disengages
it
(to
disable
reading/writing).
Index
sensor
Two
pairs
of LEDs
and
phototransistors
are
installed
to
tell
whether
the
recording
medium
is
l-sided
or
2-sided.
The
distinction
is
accomplished
by detecting
an
index
hole
on
the
medium
for
index
pulse
generation.
QO track
sensor
With
respect
to
the
carriage
position,
the
O track
sensor
detects
the
magnetic
head
at
track.0
position
and
causes
the
TRACKOO-N
signal
to be
generated.
Auto-ejector
mechanism
The
auto-ejector
mechanism
consists
of
a spring-and-latch
arrange-
ment
capable
of
the
following
functions:
(a)
Upon
insertion
of
floppy
disk
The
floppy
disk,
upon
insertion,
is not
latched
and
is
rejected
until
it
is
in place.
This
function
accurately
positions
the
floppy
disk
center
hole
to
the
spindle,
protecting
the
hole
from
damage
and
preventing
track
dislocation.
(b)
Upon
disk
removal
Opening
the
door
allows
part
of
the
floppy
disk
to pop
out
of
the
FDD.
File
protection
The
file
protection
mechanism
comprises
a pair
of LED
and
photo-
transistor,
and
a logic
circuit.
It
checks
if
the
floppy
disk
jacket
has
an
inhibit
notch.
If the
notch
is
found
to be present,
data
write
operation
is
inhibited.
Spindle
motor
controller
The
spindle
motor
controller
is
an
electronic
control
circuit
that
keeps
the
brushless
direct
drive
motor
turning
at
a constant
speed
by
accommodating
load
changes.
Electromagnetic
door
lock
mechanism
In
this
mechanism,
an
electromagnetic
door
lock
solenoid
is
driven
by a control
signal
from
the
FDC
to
lock/unlock
the
door.
2.2.2
Control
Electronics
(1)
The
control
electronics
consists
of control
logic
circuitry
com-_
prising
read/write
control
circuits,
and
controls
the FDD
accord-
ing
to instructions
from
the FDC.
With
model
A,
the VFO
circuit
is part
of
the
control
electronics.
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