Specifications

68 Chapter 3

Troubleshooting

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).