TM 11-7021-202-12
4-10.
TROUBLESHOOTING PROCEDURES
The following procedures provide the user with troubleshooting instructions and corrective
action procedures required when maintaining the processor.
WARNING
HIGH VOLTAGE is used in this equipment.
DEATH ON CONTACT may result if safety
precautions are not observed.
CAUTION
DO NOT replace defective processor with a
spare unit until the cause of the smoke and
fire has been determined and all power
cabling has been checked out as operational
and safe.
a. Smoke and Fire. If smoke and fire are encountered when operating the processor,
immediately disconnect the processor from the power source.
b. Unit Overheating. Overheating of the processor can be caused by a number of
things (e. g., restricted airflow around the unit, defective heat exchanging within the unit
itself, defective power supply, etc.). However, an overheated condition is not always
immediately obvious to the Operator or maintenance personnel. Whenever the unit becomes
overheated, the unit's power supply will automatically shut down the processor. The
symptom will appear as a malfunction in the prime power circuits, normally resulting in
replacement of the defective unit. Refer to the PWR ON/RESET, BATT, and BITE/BOOT
Indicators Not Lit troubleshooting flowchart. Once the unit has had time to cool off, it will
return to an operational state. Depressing the PWR ON/RESET pushbutton switch will bring
the unit back on line.
If the cause of the overheating has not been located and corrected, the processor will
continue to operate only as long as it takes to become overheated. Then, once again, it will
automatically shut down. Therefore, the only real clue that the unit may be overheating is
that it keeps shutting down, and after a period of time has passed and the processor has
had time to cool down, it returns to an operative condition without repairs being performed.
NOTE
Overheating of the unit is not the only possible
cause of the symptom described in the above
paragraphs. If the problem persists after
airflow restrictions are cleared, the problem is
not within the scope of this manual.
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