8300
6.9 DYNAMIC POSITIONER ADJUSTMENTS
The dynamic tests and adjustments required
to
ensure proper operation
of
the Positioner
Servo are contained in the
following
paragraphs. Although these tests and adjustments
may be performed independent
of
the static tests and adjustments, they must be
performed when the procedures contained in Paragraph 6.8 are performed.
6.9.1
POSITIONER PREPARATION, DYNAMIC TESTS
The following
functions
are
required to prepare the positioner for calibration.
(1)
Remove power from the
disk
drive.
(2)
Verify that connector J205 is connected
to
the Servo PCBA.
(3)
Remove Emergency Unload jumper plug J128 from the Logic PCBA.
(4)
Remove the interface connector and terminator board from connectors
J101
and
J10210cated on the Logic PCBA.
(5)
Install PERTEC Hand-Held Exerciser Model
TE-D01
(or equivalent)
into
interface
con nector
J1
01
.
(6)
(200
tpi
Only). Connect a jumper between
TP1
on the Servo PCBA and
TP5
on the
Temperature and Write Compensation PCBA.
(7)
(200 tpi Only) Disconnect connector J215 from the Servo PCBA.
(8)
Apply power to the
disk
drive and allow
it
to come SAFE.
(9)
Insert a
disk
cartridge
into
the disk drive.
(10) Depress the
RUN
I STOP switch once and observe that the
positioner
loads the
heads after approximately
33
seconds.
(11) Observe that the
disk
drive comes
to
READY in approximately
57
seconds.
NOTE
The READY
light
may
be
delayed 3
or
6
minutes,
depending
on
the
options
installed
in
the
disk
drive.
CAUTION
ALL
DYNAMIC
CAL/BRA
TION TESTS REQUIRE THA T
THE DISK DRIVE ROTA
TE
THE DISKS A T THEIR DESIGN
SPEED; OPERA T/ON
A T
ANY
OTHER SPEED
CAN
CAUSE
DAMAGE
TO
DISK RECORDING SURFACES
AND
HEADS.
6.9.2 DYNAMIC ADJUSTMENTS
6.9.2.1 Test Configuration
(1)
Prepare the positioner as described in Paragraph 6.9.1 .
(2)
Set the oscilloscope as follows.
• Set Channel 1 sensitivity to 0.2v per division.
• Con nect Chan nel1
X10
test probe
to
TP20
(X
+ 0).
• Set Channel 2 sensitivity
to
0.01
v per division.
• Connect Channel 2
X10
test probe
to
TP16 (velocity feedback).
• Using a
X10
probe, connect oscilloscope External Trigger Input
to
TP12 (busy
time
F I
F)
on the Logic PCBA.
• Set the horizontal sweep rate
to
0.5 msec per division.
• Use normal sync, external trigger mode, and trigger slope negative.
6-26
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