HP 7925D Service Manual page 137

7925
Removal and Replacement
* Measurements made with the actuator
assembly in a Hewlett-Packard
Shielded Shipping Package, part
number 07925-60080.
on aircraft navigation instruments
(e.g., c01npass) during air shipment.
When air shipping this assembly, you
must comply with all applicable
domestic and foreign regulations.
For shipping into or within the
United States, follow the U.S. De-
partment of Transportation (DOT)
Regulations, Title 49, Parts 171-177
(Hazardous Materials). For foreign
air shipments, follow the Inter-
national Air Transport Association
(lATA) Regulations, Article 1052. The
magnetic field strength for one ac-
tuator assembly is shown below.
REF 7311-55
Figure 5-3. Head Positioning
DISTANCE
[Metres (Feet)]
0.90 (2.95)
2.13 (7.0)
4.60 (15.0)
FIELD STRENGTH
UNSHIELDED SHIELDED*
(Milligauss) (Milligauss)
275.0 7.63
25.3 0.57
3.1 0.06
f.
Remove the two retaining screws (8 and 9) that secure
the carriage latch and detector assembly to the ac-
tuator assembly.
g. Install replacement assembly and hold in place with
retaining screws. Do not tighten retaining screws.
h. Connect the wiring connectors.
i. Adjust the carriage latch and detector assembly posi-
tion so that the carriage back flag on the coil/carriage
assembly travels through the approximate center of
the photoswitch, ensuring that there is no contact
between components.
j. Tighten the retaining screws.
I
CAUTION
I
To avoid damage to the disc drive, do not
move the carriage out more than 1.3 cm
(0.5
in.).
k.
Check the latching action by pressing in the solenoid
plunger and pulling out the carriage. Then press in
the carriage and latch the assembly. Ensure that the
latching action is smooth.
5-20. ACTUATOR ASSEMBLY
REMOVAL AND REPLACEMENT
WARNING
The magnetic field of the actuator
assembly can have dangerous effects
Note: Regulations in effect at the
publication of this manual
allow air shipment of up to
three (3) actuator assemblies
in the Hewlett-Packard
Shielded Shipping Package,
part number 07925-60080,
without special labeling as a
restricted article. (The HP
shielded shipping package
consists of a steel drum with
specially designed shielding
and padding. Do not alter or
substitute.) Air shipment of
four (4) or more actuator as-
semblies (in the shielded
package) must be labeled as
restrictd articles.· If the
shielded package is not
available, each actuator
must be packaged separately
and shipped as a restricted
article. Restricted articles
require several magnetic
warning labels and a certifi-
cation of magnetic field
strength. Consult your
nearest Restricted Article
Coordinator before air
shipment of any magnetic
assembly. The coordinator
will know of changes (if any)
in regulations and proper
labeling of restricted arti-
cles. Questions may also be
directed to the Restricted
5-9