HP 16500A Service Manual page 86

HP 16500A/16501A - Service
Description of Mainframe Tests
Below is a brief description of each mainframe test. After a test is run, the status advisory for each test
changes from UNTESTED to PASSED or FAILED. Except for the Color Display Test and the All System
Tests, when a test is selected from the Mainframe Test screen, a test screen for that specific test is
displayed.
Note
If a mainframe test fails, refer to section 6-7, "Troubleshooting."
ROM Test
This test checks the mainframe ROM on the microprocessor board. The test computes a checksum for
the ROM and compares it to a stored value. For ROM Test failures, suspect a faulty microprocessor
board.
RAM Test
This test checks the mainframe RAM on the microprocessor board. The test performs a non-destructive
pattern write/read at every location. The initial RAM contents are restored after the test. For RAM Test
failures, suspect a faulty microprocessor board.
HP-IB Test
The HP-IB Test checks the basic interface functions of the HP-IB port. Only the internal portions of the
port circuitry is tested. For HP-IB Test failures, suspect a faulty microprocessor board.
RS-232C Test
This test checks the basic interface functions of the RS-232C port. Both internal and external portions of
the port circuitry are tested. In order for the RS-232C test to pass, the RS-232C loopback connector
must be installed on the microprocessor board rear panel. For RS-232C Test failures, verify the
connection of the RS-232C loopback connector, then suspect a faulty microprocessor board.
HIL Test
The HIL Test consists of three parts: the HIL controller test, the front-panel test, and the touchscreen test.
All three tests return a pass or a fail message. This test cannot be run repetitively. Every time the Run
field is touched the HIL test sequence is repeated.
The HIL controller test checks the control circuitry on the microprocessor board. For HIL controller test
failures, suspect a faulty microprocessor board.
The front-panel test checks the front-panel circuitry for correct operation. For front-panel test failures,
verify the connection and continuity of the front-panel to microprocessor board cable. If a problem is not
found with the cable, then suspect a faulty front-panel board.
The touchscreen test checks for light pulses between LED (light emitting diode) pairs. For Touchscreen
Test failures, clean the screen and the surrounding area and move any objects blocking the screen when
you turn on the mainframe. Verify the continuity and connection of the cable from the microprocessor
board to the front-panel board. If a problem is not found with the cable and the Touchscreen Test still
fails after cleaning the instrument, suspect a faulty front-panel board.
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