(6)
Change vertical sensitivity to
20
mv
per division and change vertical positioning to
observe the edge
of
the waveform envelope.
(7)
For each head selected, observe the edge of the waveform and compare
it
to the
relevant waveform shown in Figure
6-25A
or
6-25B.
6.14.5.2 Adjustment Procedure
(100
tpi only)
If
radial alignment is required, perform the following adjustment procedure.
(1)
Maintain the oscilloscope settings established in Paragraph 6.14.5.1.
o If the IBM
or
3M-type
CE
cartridge is used, observe the waveforms shown in
Figur:e
6-25A
or
6-25B
and determine which direction the heads must be moved.
o If the CDC-type
CE
cartridge is used, observe the waveforms in Figures
6-27A
or
6-27B
and determine which direction the heads must be moved.
NOTE
If
no waveform
is
observed
at
TP19,
and
no
malfunction
of
the
disk
drive
is
suspected, a gross
adjustment
of
the
heads is required.
To
determine
which
directiun the
heads
must
be moved, use the exerciser to reposition the
heads to
cylinder
address 90
and
change Channel 1
sensitivity
to 0.1v
per
division. Increment the
cylinder
address, one
cylinder
at
a time,
until
the
correct
waveform
is observed
at
TP19;
note
this address. Refer to Figure
6-29.
(2)
Locate the two radial positioning screws
on
the selected head.
(3)
By
loosening one screw and tightening the other, position the selected head until
the correctly aligned waveform (Figure 6·25A or 6·25B for
IBM and 3M-type
CE
cartridges or Figure
6-27A
or
6-278 for the CDC-type
CE
cartridge) is obtained.
Then tighten both screws without disturbing the adjustment.
(4)
Align both heads in the same manner.
(5)
Using the exerciser, position the heads to cylinder
000,
then reposition them to
cylinder
105
and observe that the waveform still appears
as
in Step
(4).
This
ensures that the heads have not been aligned to cylinder
105
which is a duplicate
of cylinder
100.
NOTE
If
a head
cannot
be
adjusted
to
obtain
the
minimal
lobe
pattern, the head may
not
be
flying
correctly. This
condition
can be caused
by
either
a
dirty
disk
or
head,
incorrect
head load force,
or
damaged head(s).
6.14.5.3 Adjustment Procedure
(200
tpi only)
CAUTION
THE POLARITY OF THE COMPENSATION VALUE FOR
EACH CE
CARTRIDGE IS CRITICAL. IF CARTRIDGE
INTERCHANGE
IS
NOT A PREREQUISITE, PERFORM
THE ADJUSTMENT PROCEDURE FOR FRONT LOADING
100
TPI
MODELS DESCRIBED IN PARAGRAPH 6.14.5.2
EXCEPT
USE FIGURE 6-26 INSTEAD
OF
FIGURE
6-24
REFERENCED IN THIS NOTE.
(1)
Allow the disk drive to stabilize in the
Ready
mode for
30.
minutes (minimum).
(2)
Maintain oscilloscope settings established
in
Paragraph
6.14.5.1
except change
Channel 1 sensitivity to
50-100
mv
per division.
To Next Page
Loading...