48 IBM Desktop System HMM
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.
Factory-Installed Storage Devices
Use this check procedure to test any factory-installed
drives, including Zip drives.
ATTENTION:
The customer may have customized
settings in the Configuration/Setup Utility (other
than default settings) on the computer you are
servicing. Running the Configuration/Setup
Utility might alter those settings. Take note of
the current settings and verify that the
customer settings are in place when service is
complete.
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