Specifications

66 Chapter 3
Troubleshooting
Functional Diagnostics (Step 2)
Functional Diagnostics Menu
To run the functional diagnostics, see “Accessing the Diagnostic Tests”
on page 62.
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.