6300
6.7 POSITIONER SERVO CALIBRATION
Paragraphs 6.8 and 6.9 describe the test configurations, test procedures, and adjustment
procedures
relevant
to
both
static
and dynamic operation
of
the
D3000
Positioner Servo. It
is important
to
note that
if
static positioner adjustments are performed the dynamic
positioner adjustments must
also
be
performed.
To
ensure accurate calibration of the positioner, the preliminary tests and adjustments
described in Paragraph 6.7.1 must
be
performed prior to calibration of the positioner.
NOTE
The
only ground reference test
point
to be used
for
measurement purposes is
TP1.
All
test
points
referred to
are located on the Servo
PCBA unless otherwise noted.
6.7.1 POSITIONER PREPARATION FOR STATIC TESTS
The following
functions
are required
to
prepare the positioner for calibration.
(1) Remove power from the
disk
drive.
(2) Disconnect connector
J205 from the Servo PCBA.
WARNING
TO
PREVENT INJURY
TO
THE
SERVICE ENGINEER
DUE
TO
INADVERTENT ACTIVATION OF
THE
POSITIONER
DRIVE, CONNECTOR
J205
MUST
BE
REMOVED FROM
THE
SERVO
PCBA
PRIOR
TO
ANY
SERVO
TESTS
OR
ADJUSTMENTS.
(3)
Install Emergency Unload Bypass Jumper at connector J128 on the Logic PCBA.
(4)
Apply power
to
the disk drive. Observe that the SAFE indicator becomes
illuminated, and that the
bulb in the
lampllens
assembly (see Figure 7-7 and
Table 7-7) is illuminated.
(5)
Insert a disk cartridge into the disk drive.
(6)
Measure + 10.7 ± 0.8v between
TP1
and TP21.
(7)
Measure
-10.1
±0.8v
between
TP1
and TP25.
(8)
Measure regulated + 5.0
::I:
0.25v between
TP1
and TP4.
(9) Measure regulated
-5.0
::I:
0.25v between
TP1
and TP12.
(10)
Voltages in Steps (6) through (9)
must
fall
within
the
limits
specified.
In
the case
where voltages measured
fall outside these
limits,
perform the test and
adjustment procedures described in Paragraph 6.6.2.
(11) Manually move the positioner carriage back and forth and check that the reticle-
to-scale gap across the
full length
of
the scale is approximately 0.127 mm
(0.OO5-inch).
Do
not load heads
onto
the platter at
this
time. A mylar shim can be
used
for
this
measurement. The SAFE indicator
will
extinguish when the shim is
in
place between the reticle and the scale.
(12)
NOTE
The
Read/Write PCBA may be removed to facilitate
access to the scale. Perform Steps [12] through [14J
only
if
the reticle-to-scale gap does
not
meet the
approximation given in
Step [11J.
Loosen the horizontal. hex-head screw at the base of the receiver post. This
will
loosen the receiver post and allow it
to
be
raised and lowered when the Allen-head
screw located inside the
hollow
of
the
receiv~r
post is rotated.
6-14
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