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1.4
FUNCTIOhl"\L DESCRIPTION
OF
THE
DRIVE
The Disk Drive.
is
futtyself-contained
and
requires'no operator intervention during normal operation. The
Drive consists of aspindle drive system, ahead positioning system, and read/write/erase system.
When the front latch
is
opened, access
is
provided for the insertion
of
adiskette. The diskette
is
positioned in
place by plastic guides, and the front latch. Inlout location
is
ensured·when the diskette
is
inserted until a
back stop
is
encountered.
Closing the front latch activates the conelclamp system resulting in centering
of
the
diskette
and
clamping
of
the diskette
to
the drive hub. The drive
hub
is
driven
at
aconstant speed
of
300
rpm
by
aservo controlled dc
motor. In operation, the magnetic head
is
loaded into contact with the recording medium whenever the front
latch
is
closed.
The magnetic head
is
positioned over· the desired track by means
of
a4-phase stepper motor/ba,nd assembly
and
its associatedelectronics. This positioner employs aone-step
rotation
to
cause a1-treck Unear' movement.
When awrite-protected diskette
is
inserted into
the
Ddve, the write;;protect senior disables
the
write
electronics of the Drive and
an
appropriate signal is applied
to
the interface.
When performing awrite operation, a0,33
mOl
(0.013-inch) (nominal)
data
track is recorded. This ,track
is
then tunnel erased
to
0,30
mOl
(0.012 inch) Cnominal).
Data recovery electronics include alow-level read amplifier, differentiator, zero-crossing detector,
and
digitizing circuits.
No
data decoding facilities are provided in the basic Drive.
The Drive
is
also supplied with
the.
following sensor systems:
(1)
ATrack 00 switch which senses when the Head/Carriage assembly
is
positioned
at
Track
.,.
(2)
The index sensor, which consists
of
an
LED'Ught source
andphototransistor,
is positioned such
that when
an
index hole is detected, adigital signal is guaranteed. The index sensor used
is
ahigh
resolution device which can distinguish holes placed close together, i.e., Index-Sector holes in a
hard sectored diskette.
(3) The write-protect sensor disable
the
Disk Drive electronics whenever awrite-protect
tab
is
applied
to
the disketteCsee section
.1.
16 and figure 6).
1.5
DISKETTES
The
TM
100
uses astandard
133.4mm
(5.25
inch) diskette. These diskettes are available with asingle Index
hole
or
multiple holes.
Diskettes with asingle hole are used when secto.rinformation
is
prerecorded on the diskette. Multiple hole
diskettes provide sector information
by
means of the index sensor
andelectronicl.
Figure 2is asimpUfied drawing
of
the
diskette used with the Disk Drive. It
can
be
saenthat
this recording
medium
is
aflexible magnetic disk enclosed in aprotective Jacket. The protected disk, free to
rotate
within
the jacket,
is
continuously cleaned by
th,
soft fabric lining
of
the Jacket during normal operation. LINER
1.6
MECHANICAL·AND ELECTRICAL SPECIFICATIONS
The mechanical
and
electrical specifications for the
Disk~rive
are given in Table 1.
1.7
INTERFACE
SPECifiCATIONS
Levels: True
II:
+O.4v(maximum)
False =+2.4v (minimum)
The interface circuits are designed so
that
adisconnected wire results in afalse signal.
1.8
UNCRATING THE DISK DRIVE
The Disk Drive is shipped
ina
protective container which, when bulk packaged, minimizes the possibility
of
damage during shipment. The
follOWing
procedure describes
thetecommended
method
for uncfatlng
the
Disk
Drive. (1) Place the container
on
aflat work surface.
(2) Remove the outer cardboard sleeve from around the Inner container.
(3) Remove the upper half
of
the
inner-container.
(4) Remove the Disk Drive from the lower half
of
the inner container.
(5) Check the contents
of
the
shippingcontainer against the packing
sUp.
Investigate
the
contents
for
possible.damage; notify the carrier immediately
If
any damage
Is
noted.
RECORDING MEDIUM
Fig. 2
1.9
PHYSICAL CHECKOUT
Before applying power
to
the unit, the following inspection should
be
performed:
(1)
Front'atch.
Check that the
front
latch opens
and
closes. Note that when the door
is
opened, the
head arm raises.
(2) Ensure
that
the front panel
is
secure.
(3) Manually rotate the drive hub. The
hub
should rotate freely.
(4) Check
that
PCBA's are secure. Check that the connectors are firmly seated.
(5) Check for debris
or
foreign material between the heads and remove same.
