GENERAL PROCEDURES SUMMARY
a. Determine the equipment to troubleshoot from the failure symptoms listed in TM 1-1520-238-T-2.
If faulty equipment is not known and a failure symptom exists, use failure
symptom list in TM 1-1520-238-T-2 to determine system.
b. Select the chapter, section, and paragraph to use. (Refer to information on using this volume in HOW TO
USE THIS VOLUME).
c. For use of external power and the ground service utility connectors, refer to TM 1-1520-238-23. If external
power is not available, refer to TM 1-1520-238-23 for the application of the auxiliary power unit (APU). Refer to
TM 1-1520-238-23 and TM 55-1730-229-12 for application of external electrical and hydraulic power and
pressurized air. External power is preferred however, for onboard power the APU may be used.
d. During power up procedures, if circuit breakers do not stay closed refer to TM 1-1520-238-T-2 to identify
the location of corrective procedures.
e. During power up procedures, if power is not available to the equipment, refer to TM 1-1520-238-T-6 to
troubleshoot the electrical system.
f. Troubleshoot using specific procedures in the selected paragraph.
Turn off power before detaching or attaching wires and connectors. High
current 28 VDC or 115 VAC is present. Failure to do so could result in
death or serious injury.
To prevent injury, disable the aft avionics bay door fan before performing
maintenance or troubleshooting in the aft avionics bay.
When making resistance, open, short, or other ohmmeter checks on
circuits, always deenergize the circuit to avoid damage to the meter.
a. Correct faults and repair any equipment where damage is obvious.