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Troubleshooting
Failing Parts or Assemblies:
The check procedures generally
help you trace a problem to one part or assembly. The last step
of the specific check procedure you are using indicates that a
part or assembly is failing. You should inspect the part or
assembly before you decide to replace it. It might be loose,
dirty, or in need of a small repair. The check procedures might
lead you to two, or even three, possible failing parts or
assemblies. The parts that might be failing are listed in order of
the most probable failure. Also, the FRU parts are defined as
replaced units and are not repaired in the field.
Measuring Voltages:
Some check procedure steps instruct
you to measure voltages on cable plugs and electronic board
connectors. If you are asked to measure voltage at several
places on a plug or connector, a chart next to or near the
instruction indicates the number of the plug or connector, the
pin numbers you should measure, the signal name, and the
correct voltage for the condition you are measuring. Measure
the voltage only at the pins listed in the chart. Remember to set
the meter on the correct scale and to put the meter leads in the
correct position for the voltage you are asked to measure.
NOTE:
Use frame ground as the ground reference. Attach
the black (ground) lead of meter to frame ground,
except where specified otherwise.
