Troubleshooting and Repair
This section provides troubleshooting and repair techniques and
information. Read the Safety Summary at the front of this manual
before servicing the instrument. Before performing any procedure,
review it for cautions and warnings.
W A R N I N G
When power is applied there are dangerous voltages present in this
equipment. Maintenance should be performed by trained service personnel.
When maintenance can be performed without power applied, the power
cord must be removed from the instrument. Maintenance by persons
unaware of the hazards involved (for example, fire and electric shock) can
result in injury or death.
To troubleshoot the power supplies
The circuitry consists of simple power supplies. Use conventional
troubleshooting techniques. A complete parts list, component locator, and
schematics are provided later in this chapter.
Following are some things to check first, given certain failure symptoms.
This is not a comprehensive troubleshooting guide.
The +17.3 supply won’t adjust into tolerance
•
Make sure the supply is not loaded into current limit.
•
Check the +1.5 V reference of the +17.3 V regulator.
•
Check the values of parts in the voltage divider stick that includes the
adjustment potentiometer (R37–R39).
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Summary of Contents for 1143A
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