6.14.1.3 Cylinder
095
(190
on
200
tpi)
This cylinder has a single flux transition marker recorded approximately
180
degrees from
the center
line of the index slot.
To
assist in Identifying this marker, a burst of flux
transitions occurs
10
j-lsec
after the marker.
Cylinder
095
(190
on
200
tpl) is used for circumferential adjustment of the (upper)
photoelectric sensor.
Information recorded
on
this cylinder is similar to that recorded
on
the top load
CE
disk
cartridge in cylinder
005.
NOTE
On
the
100
tpi
front loading
CE
cartridge, in cylinder
105
there
is
another cylinder written eccentric to the disk
rotational center. Because
of
its identical appearance to
the true radial alignment cylinder
[100]
it
is
possible to
become confused
and
misalign the heads on the incorrect
cylinder. Care should be used when performing
a radial
adjustment with front loading cartridges to avoid this
misalignment caused
by
incorrectly using the pattern in
cylinder
105.
6.14.2
TOP
LOADING
CE
DISK CARTRIDGE
The 100 tpi top loading
CE
disk cartridge contains two pre-recorded cylinders
005
and
073
which are used during adjustment procedures
to
the head/arm carriage assembly and to
the upper magnetic transducer.
The
200
tpi
CE
disk cartridge Is Identical to the 100 tpi cartridge except that the two
pre-recorded cylinders are
010
and 146.
CAUTION
WHEN USING
100
TPI
CE
PACKS, ENSURE
THA
T
CYLINDERS
004, 005, 006,
AND
071
THROUGH
075
ARE
NOT INA DVERTENTL Y WRITTEN ON. WHEN USING 200
TPI
CE
PACKS, ENSURE
THA
T CYLINDERS 008
THROUGH 012
and 142 THROUGH
150
ARE NOT
INADVERTENTL Y WRITTEN ON. WRITING ON THESE
CYLINDERS WILL CAUSE
PRE-RECORDED DATA
TO
BE
DESTROYED.
6.14.2.1
Cylinder
073
(100
tpi), Cylinder 146
(200
tpi)
For100 tpl
CE
packs, cylinder
073
is used
for
adjustment of the headl arm location; for
200
tpi, cylinder 146 is used for this adjustment. Two circular concentric cylinders, either side
of
cylinder
073
and cyl inder 146, are spaced 0.010-inch apart and
are
eccentric to the
center
of
rotation
of
the disk
by
0.0015-inch.
The
cylinders
are.
written with slightly
different frequencies. Radial adjustment
of
the head
is
carried out by monitoring the beat
frequency at cylinder
073
(100
tpi), 146
(200
tpl). A head that is correctly centered over
track
073
(100
tpi), 146
(200
pti), gives
an
oscilloscope trace with
an
equal 2-lobe fringe
pattern.
Due
to the amount
of
eccentricity, when a head is reading the pattern and the head
is misaligned from the true cylinder radius, then a lobed envelope pattern will
be
produced.
6-52
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