Maintenance; Introduction; Maintenance Precautions; Standard Test Equipment - HP 7925D Service Manual

This section contains maintenance precautions, listings
of special tools and test equipment, preventive mainte-
nance routines, and preventive maintenance inspection
and cleaning procedures. Maintenance of the disc drive
must be performed by service-trained personnel only.
2-1. INTRODUCTION
WARNING
This disc drive does not contain
operator-serviceable parts. To pre-
vent electrical shock, refer all instal-
lation and maintenance activities to
service-trained personnel.
MAINTENANCE
I~
• Use only the type of alcohol specified in
table 2-1. Some other brands contain im-
purities that could cause damage.
• Avoid applying excessive pressure to the
gimbal area of the head while cleaning.
Excessive pressure may alter or damage
the head characteristics which are preci-
sion set at the factory.
• Never place an inspection mirror bet-
ween the heads or allow it to touch the
heads. The flying characteristics of the
heads may be altered or damaged.
• Do not use oil or other similar lubricants
anywhere in the disc drive.
2-2. MAINTENANCE PRECAUTIONS
To avoid injury to personnel and to prevent damage to
equipment, observe the following safety precautions:
WARNING
• Do not attempt to manually extend the
carriage assembly, unless the head load-
ing tool (part no. 13354-60023) is
clamped to the carriage assembly and
there is no disc pack in the disc drive,
otherwise head damage will result.
• Observe all warnings and cautions
provided in this manual and that are
placed on the equipment.
2-3.
SERVICE TOOLS AND
TEST EQUIPMENT
• Use extreme caution when working
on the disc drive with shroud re-
moved or doors opened. Hazardous
voltages are present inside the main-
frame when the power distribution
assembly is connected to an active ac
power source.
The following paragraphs list and describe the tools and
test equipment required to service the disc drive.
2-4. STANDARD TOOLS
Recommended standard tools and materials required for
service are listed in table 2-1. Except where noted, equiva-
lent tools may be substituted.
• Do not attempt to remove or change
printed-circuit assemblies, intercon-
necting cables, or extender cards
while power is applied.
2-5. STANDARD TEST EQUIPMENT
I
CAUTION
I
• Do not run the disc drive without an
absolute filter. Severe contamination in
the head/disc area will result which
could damage the head and/or disc sur-
face.
• Use only the brands of cleaning material
specified in table 2-1. Some other brands
contain contaminating oils and/or lint
which may leave a harmful residue.
The standard test equipment required for maintenance
are as follows:
a. Digital Voltmeter, HP 970A or equivalent battery-
operated digital voltmeter.
b. Oscilloscope, HP 180A, or equivalent.
2-6. SPECIAL TOOLS
Table 2-2 lists the special tools required for maintenance.
Figure 2-1 depicts the special tools.
2-1