TROUBLESHOOTING AND REPAIR
PARTS REPLACEMENT 6-22.
An experienced technician should be able to isolate the defective component and
replace it after reading "FUNCTIONAL DESCRIPTION" (in Section 2) and the
troubleshooting information contained in this section. Schematics are in Section 8.
Most parts are replaced using ordinary methods. However, chip components requiring
special attention. To replace the chip components, use a 600° F soldering iron, such as
an Ungar 50T7, with a number 76 heater, a number 88 tip, and 2% silver solder paste,
such as Electro Science Fabrication SP -37D1 or similar wire solder.
Replacement of some components may require that alignment, compensation, and/or
calibration procedures be performed. See the sections of this manual appropriate to
the circuit functions being restored. Use the performance tests in Section 4 to verify the
results of the repairs.
SELF-TEST DESCRIPTION 6-23.
The instrument self-tests are performed on power-up or when initiated by Special
Function 02. If any test fails, the message "FAIL" is displayed along with the
corresponding status code. A complete list of the test failures is displayed upon
completion. Use the key to scroll the list if there are more than four failures.
During the tests, the RPP relay is opened to protect instruments connected to the RF
output from possible damage.
Special Function 904 runs the self-tests in a troubleshooting mode. It stops after each
test that fails leaving the hardware in the test configuration and the error code in the
display. The RF output is enabled so measurement equipment can be connected. Press
any key to continue the test.
The self-test results (see Table 6-2) can be displayed by entering Special Function 03.
Status code 00 indicates that there were no failures. Status code 301 indicates that the
tests were aborted before completion and that the reported results may be incomplete.
Table 6-2. General Self-Test Results
CODE
00
301
DESCRIPTION
No self-test Failures
Self-tests Aborted
Digital Tests 6-24.
The digital tests (see Table 6-3) perform basic checks of the circuitry on the A13
Controller PCA.
The calibration/compensation memory test verifies the CRC checksums of each of the
calibration/compensation data segments in the battery backed RAM (U8) and in the
EEPROM (U9). If any of the tests fail, status code 302 is reported. See "Calibration/
Compensation Memory Status" in Section 6B for further details.
6-8
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