Control Data Corporation CYBER 180 810 Maintenance And Parts Manual page 46

in order of increased hardware usage. Each of the diagnostics in the list
must run error free before the one listed below is attempted. Do not run the
entire diagnostic hierarchy. If a problem is suspected in one of the
functional areas listed in the hierarchy, run one of the diagnostics for that
functional area. If it runs successfully, run the next diagnostic in the
list. Continue running diagnostics until a failure occurs. The purpose of
the hierarchy is to allow selection of the proper diagnostic as quickly as
possible.
Below is a guide for the order of each area in which diagnostics should be run:
Peripheral Processors
I/O Channels
Central Memory Access Hardware
Central Memory
Central Processor
Computer System
If available off-line diagnostics fail to detect a failure, use on-line
diagnostics as a last resort for detection of failures.
TROUBLESHOOTING TECHNIQUES
Methods used to locate problems are troubleshooting techniques. The aim of
good troubleshooting practices is quick location and correction of a problem.
Troubleshooting may be categorized under the following basic headings:
Selective isolation
Voltage margin tests
Timing margin tests
Shotgunning
'·
SELECTIVE ISOLATION
Selective isolation is the technique of locating faulty modules by
interchanging suspected modules with modules of the same type that are known
to be good. This technique assumes that the symptoms provide an indication to
the source of the trouble.
CAUTION
Exercise the utmost care when using
this procedure for 210-pak modules.
ESD procedure (refer to ESD Control)
must be carried out to ensure no damage
to any paks. Careless handling may
result in any of the following:
• Damage to a module installed upside
down or in an incorrect location.
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