Chapter 5 Service
Self-Test Procedures
104
Self-Test Procedures
Power-On Self-Test
Each tim e the power suppl y is power ed on, a s et of s elf- tests are performed.
These tests check that the minimum set of logic and measurement hard ware
are functioning prope rly . The power-on self-test performs checks 601 through
604 and 624 through 632.
Complete Self-Test
Hold any front panel key except the ‘‘Error’’ key for more than 5 seconds while
turning on the power to perform a complete self-test. The power supply beeps
when the test starts. The tests are perform ed in the order shown below.
601
Front Panel Does not respon d
The main controller U19 attempts to
establish serial communications with the front panel controller U1 on the front
panel board. During this test, the U1 turns on all display segments.
Comm uni cation mu st function in both directio ns for this test to pass. If this
error is detected during power-on self-test, the power supply will beep twice.
This error is only readable from the remote in terface.
602 RAM read/write failed
This test writes and reads a 55h and AAh checker
board pattern to each address of ram U14. Any incorrect readback will cause
a test failure. This error i s only readable from the remote interface.
60 3 A/D sync stuc k
The main controller issues an A/D sync pulse to U19 and U20
to latch the value in the ADC slope counters. A failure is detected when a sync
interrupt is not recognized and subs equent ti m e-out occurs.
604
A/D slope convergence failed
The input amplifier is configured to the
measure zero (MZ) state in the 10 V range. This test checks whether the ADC
integrator produces nominally the same number of positive and negative slope
decisions (±10%) during a 20 ms interval.
605 Cannot calibrate rundown gain
This test checks the nominal gain between
integrating A DC and the U19 on-chip ADC. This error is reported if the
procedure can not run to completion due to a hardware failure.
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