Fluke 900 - Manual (Page 25)

FLUKE 900 SERVICE MANUAL Selftest
3 Selftest
3.1 Reading Selftest Results
Immediately after poweron, the tester executes a series of selftests that take about one minute.
The selftests may also be initiated at any time by simultaneously pressing (.
cntrj and (^. The
tests are number^ 0 to 55 and all but a few are run automaticaUy. These few plus a number of
"extended tests" denoted by Exx (eg. E60), can be run by manually keying them in when analyzing
a problem. All the tests may be run individually in this way to produce "individual test results".
When a failure is encountered during poweron selftest, two rows of digits display "general results"
and sometimes a third and fourth row appear. Rows 1 and 2 indicate the failing test numbers;
rows 3 and 4 indicate fault flags that are tied to memory and shift registers. Flag failiues indicate
major functional problems and general test results indicate which tests are failing. "Individual test
results" are more detailed dispays of the failing tests and they indicate which channels (lines) ate
faulty.
In cases where a failure is severe and the LCD screen may not function, the LEDs around the
ZIF socket may indicate the problem.
Hardware and software problems occasionally result in system crashes that present a message on
the command line. One cause of such a crash is a corrupted simulation library file. A summary of
these messages appears in Section 3.4.
3-1