Chapter 5 Service
Self-Test Procedures
99
5
Self-Test Procedures

Power-On Self-Test

Each time the power supply is powered on, a set of self-tests are performed.
These tests check that the minimum set of logic and measurement hardware
are functioning properly. The power-on self-test performs checks 601 through
604 and 624 through 634.

Complete Self-Test

Hold any fron t pa nel key exc ep t the "Er ror '' k ey f or m ore tha n 5 s eco nds whi le
turning on the power to perform a complete self-test. The power supply beeps
when the test starts. The tests are performed in the order shown below.
601 Front Panel Does not respond The main controller U17 on the top board
attempts to establish serial communications with the front panel controller U7
on the front panel board. During this test, U7 turns on all display segments.
Communication must function in both directions 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 interface.
602 RAM read/write failed This test writes and reads a 55h and AAh checker
board pattern to each address of ram U15 on the top board. Any incorrect
readback will cause a test failure. This error is only readable from the remote
interface.
603 A/D sync stuck The main controller issues an A/D sync pulse to U17 and U16
on the top board to latch the value in the ADC slope counters. A failure is
detected when a sync interrupt is not recognized and subsequent time-out
occurs.
604 A/D slope convergence failed The input amplifier is configured to the
measure zero (MZ) state in the 10 V ran ge. This test checks whether the ADC
integrator produces nominally the same number of positive and negative slope
decisions (±10%) during a 20 ms interval.