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Model 8901B
Service
Parts and Cable Locations
The locations of individual components mounted on printed-circuit boards or other assemblies are
shown adjacent to the schematic diagram on the appropriate service sheet. The part reference designator
is the assembly designator plus the part designator. For example, A6R9 is resistor R9 on the A6
assembly. For specific component descriptions and ordering information, refer to Table 6-3, Replaceable
Parts, in Section 6. Chassis and frame parts, as well as mechanical parts and cables, are identified on
Figures 6-1 through 6-6.
Major mechanical parts have reference designations that begin with the letters MP. Other mechanical
parts, such as screws, are listed in the replaceable-parts list below the part to which they fasten. To find
the part number and description of a mechanical part, find the part in one of the figures in Section 6
or Section 8. The part in the figure will be labeled with its reference designator. Look up that reference
designator in the Replaceable Parts table. If the part is a fastener, such as a screw, nut, or washer, look
to the figure for the part to which it fastens. Then, look up the fastened part in the parts list. Just
below it are the part numbers and a description of the desired hardware.
Other Service Documents
Service Notes, Manual Updates, and other service literature are available through Hewlett-Packard.
For further information about Manual Updates, refer to Volume
1,
paragraph 1-6.
Recommended Test Equipment and Accessories
Test equipment and test accessories required to maintain the Modulation Analyzer are listed in Tables
1-2 and 1-3. Equipment other than that listed may be used if it meets the listed critical specifications.
8-5. GENERAL TROUBLESHOOTING
Instrument problems usually fall into three general categories: operator errors, operation out of
specification, and catastrophic failures. The troubleshooting strategy is different for each category.
Operator Errors
Apparent failures sometimes can result from using the instrument outside of its range. Usually, the
instrument can sense the condition and will display an error message. At other times it cannot:
for example when it attempts to measure signals with frequencies higher than 1300 MHz. Consult
the Specificutions table (Table
1-1)
and the Detailed Operating Instructions in Section 3 for more
operation limitations.
Operation Out of Specification
The specifications are listed in Volume
1,
Table
1-1.
Performance tests that can be used to verify
the specifications are found in Volume
1,
Section 4 . If instrument performance is only slightly out of
limits, it can sometimes be corrected by an adjustment. The procedures for adjustments are in Volume
1,
Section 5. References listed for each adjustment indicate which service sheet to consult when the
adjustment procedure fails. In general, however, it is also a good practice to perform the troubleshooting
checks on Service Sheet BD1, since they take only a
few
minutes and reveal much information.
8A-5
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