Agilent Technologies 8935 Series, Manual

Page: 69 / 343

68 Chapter 3
Troubleshooting
AF, RF, & CDMA Diagnostics (Step 3)
AF, RF, & CDMA Diagnostics (Step 3)
NOTE
The diagnostics are intended to help in locating the source of
catastrophic failures. Occasionally, a test will fail with the test results
being only slightly out of limits. Such failures do not necessarily
indicate that the Test Set is operating outside of its published
specifications or that it is otherwise faulty. Further testing (such as
running the performance tests) will be required in such cases.
NOTE
Many of the internal diagnostic and calibration procedures use
low-level latch commands to control the instrument settings. Many
latch settings persist even through a preset. They can only be reset by
an instrument power down or by explicitly reseting each latch. This
phenomenon is the reason the message “
Direct latch write
occurred. Cycle power when done servicing
.” is displayed the first
time a latch is written to. Because latch settings persist, problems can
arise in running these programs. For example, prematurely
terminating a test in a diagnostic (using the Pause and Exit keys) and
restarting another test may cause failures in that test because of
improper latch settings. It is best to run tests to completion before
starting another one. Also, be sure to cycle the power off and on when
done servicing the Test Set.
AF Diagnostics
This program tests the audio functions of the following assemblies:
• A2A40 Audio Analyzer 2
• A2A80 Audio Analyzer 1
• A2A44 Modulation Distribution
• A2A32 Signaling Source/Analyzer (AF Generators 1 and 2 only)
• A2A33 Measurement (only a few selected inputs)
After initial cabling, all tests can be run in a loop mode without further
intervention. This makes it easier to catch intermittent failures. To run
the AF diagnostics, see
“Accessing the Diagnostic Tests” on page 62 .
NOTE
A fifteen minute warm up is required. The measurement limits of the
SERVICE4 diagnostic tests are valid only at room temperature; that is,
20º to 25ºC (65º to 75ºF).