Power-Up Self Check And Certain Aborted Measurements - IET Labs, Inc. RLC Digibridge 1693 User And Service Manual

1693 RLC Digibridge
5.7.2 Power-Up Self check and
Certain Aborted Measurements
The following outline of failure displays includes
comments on some of the self cheek routines, sig-
nificance of the displays, and some suggestions for
appropriate service procedures.
For the most rigorous self cheek, in servicing, repeat
the power-up self cheek several times , at least once
with a abort circuit as "'DUT" in the test fixture and
once with the test fixture empty (open circuit) . A nor-
mally functional Digibridge should pass both ways.
Keen observation of the fleeting displays associated
with the tests that pass, before the one that fails, are
sometimes useful. Pressing any key, such as [SHIFT]
will halt the self-test routine and bold the display until
the key is released. Look for trends or tests that pass
only marginally.
124
Figure 5-10: Timing diagram of the power-up self check.
SELF-CHECK (FAILURE) DISPLAYS
88888 8888. RAM read/write exercise failure;
Digibridge hangs up. PROCEDURE: Switch POWER
OFF and ON to clear hang up and repeat self check.
Cheek RAM circuitry and data and address buses on
1689-4702 Analog & Control board.
77777 XXXX. Detector test failure ; Digibridge hangs
up. PROCEDURE: Switch POWER OFF and ON to
clear hang up and repeat self check. Be sure that the
EXTERNAL BIAS switch is OFF. 1689-4702 Analog
& Control board requires service by trained personnel.
77777 7777. DBIG (U27 pin 2) is stuck low.
Integration failure. 1689-4702 Analog & Control
board requires service by trained personnel.
77777 6666. DMSR (U27 pin 8) is stuck high .
Integration failure 1689-4702 Analog & Control
board requires service by trained personnel.
Service and Maintenance