Service manual

4 113
Troubleshooting
External Tests Failure Troubleshooting
4. Troubleshooting
External Tests Failure Troubleshooting
If you can't identify the faulty assembly using the internal tests, you can execute the
external tests in addition to the internal tests. These external tests are also built-in tests and
9 tests are available in the HP
4294A diagnostic test mode. Refer to Table 4-2 to know
which assembly is probably faulty and should be replaced. For more information about the
external tests, see Chapter 7.
To execute the external tests, perform the following procedures.
1. Press [Preset], [System], DIAGNOSTIC TEST. Pressing EXTERNAL TEST jumps to
the first test external test, test:17 FRONT PANEL.
2. Select the test using the RPG knob, [↑], [↓] keys or ENTRY keys.
3. Press RUN TEST to execute the specified test.
4. Wait until the test result, PASS or FAIL, is displayed.
NOTE The troubleshooting procedures requiring the external tests 17,18,and 19 ars also given in
Chapter 6.
NOTE The external test 20 consists of the external tests 21 through 26. The external tests 20
through 26 require an OPEN termination ( 42090A) or two BNC cables to connect Hc and
Hp terminals, and Lp and Lc terminals. Refer to Figure 4-2.
Figure 4-2 External Test (20 through 26) Setup