(3)
Set the disk exerciser
to
the
ON
mode.
(4)
Set the disk exerciser
to
perform a one-track repetitive seek from cylinder 000
to
cylinderOO1.
6.9.2.2 Test Procedure
(1)
Select Channel 1 .
(2)
Observe the amplitude of the waveform at TP20
as
shown in Figure 6-6 while
performing a one-track repetitive seek.
NOTE
Careful observation
of
the X + 0 signal
at
TP20
will
show a
small disturbance near the forward and reverse waveform
peaks. This disturbance is normal and occurs
at
the
point
where the Servo switches into the Position mode.
(3)
Acceptable limits:
• 13.2v (maximum)
• 10.8v (minimum)
(4)
If the acceptable
limits
are not met, perform the adjustment given in Paragraph
6.9.2.3,
Step (1), before continuing
this
procedure.
(5) Check that the waveform at
TP20
is balanced about ground
as
shown in Figure6-6.
(6)
If the waveform observed in Step (5) is not balanced about ground, perform the
adjustment given in Paragraph 6.9.2.3,
Step (2), before continuing this procedure.
(7)
Check that the start
of
the waveform is balanced about ground
as
shown in
Figure 6-6.
(8)
If the start of the waveform observed in Step
(7)
is not balanced about ground.
perform the adjustment given in Paragraph 6.9.2.3,
Step (3), before continuing
this procedure.
(9)
Select Channel
2.
(10)
Observe that the start
of
the waveform at
TP16
is balanced about ground
as
shown
in Figure 6-7.
(11)
If the start of the waveform observed in Step
(10)
is not balanced about ground,
perform the adjustment given in Paragraph 6.9.2.3,
Step (4), before continuing
this
procedure.
(12)
Set osci lIoscope to Chop mode.
(13) Repeat Paragraphs 6.9.2.2,
Steps
(7)
and (10), and observe
TP20
(Figure 6-6) and
TP16
(Figure 6-7) at the same time, alternately adjusting
R22
and
R204
so that the
start of waveforms at
TP20
and TP16, respectively, are balanced about ground.
(14)
Select Channel 1 .
(15)
Move Channel 1 test probe to
TP2.
(16)
Observe the amplitude of the waveform at
TP2
(Figure 6-8) while performing a
one-track repetitive seek.
(17) Acceptable limits:
• 13.2v (maximum)
• 10.8v (minimum)
(18)
If the acceptable
limits
are not met, perform the adjustment given in Paragraph
6.9.2.3,
Step (5), before continuing
this
procedure.
6-27
6300
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