ALTERNATIVE TROUBLESHOOTING TECHNIQUES

TM 11-7025-233-23

a. Fault Discovery. Usually, the operators or supervisor will notice faulty

performance first. They must report the fault on the proper form so you will have

the facts you need for the need for the next phase.

b. Failure Confirmation. Based on the facts provided, you must confirm the

failure and define the symptom. The symptom is the first clue you will use in the

troubleshooting process.

c. Troubleshooting Entry. Using the symptom defined during phase two, find the

low chart which will help you isolate the fault in the equipment.

troubleshooting

The checkout and symptom index chart (chart-00) will help you do this.

d. Trouble Isolation. Follow the step-by-step procedures in the flow chart to

isolate and correct the cause of the equipment failure.

e. After Maintenance. When you have made the fix recommended in the trouble-

shooting procedure, you must check your work. Use the chart titled After

Maintenance Check. It tells you how to test your repair and make sure the

equipment now works as it should.

4-6. ALTERNATIVE TROUBLESHOOTING TECHNIQUES

When a failure causes a symptom which is not covered in the symptom index or not

corrected by the troubleshooting procedure in the flow chart, you must try

alternative techniques.

a. Understand Principles of Operation. Sometimes the symptom may have no

specific procedure given to troubleshoot it. When this happens, remember that the

equipment always operates the same way. By comparing the faulty operation with

expected or normal operation you may find the cause of the failure and be able to

fix it.

CAUTION

All circuitry on the power supply board has

direct connection to the ac power line. Do not

make any continuity checks on this board unless

the test instrument is connected to an isolation

b. Check the Circuits. All electronic equipment uses circuits to route power

through the components. Any break in continuity will cause some type of failure.

By running continuity checks on suspect circuits you may find the cause of the

failure. Use the schematic diagrams in appendix D to check the circuits in this

equipment.

c. Check Past Maintenance Records. If the unusual failure occurred before, it

should appear in the maintenance records for the equipment. The records should

also tell you how the failure was corrected. Use the same fix this time.

a. Trial and Error Repair. Usually trial and error repairs should be avoided.

They are costly and can induce additional symptoms. However, when your experience

with the equipment leads you to suspect a definite cause, you should try the repair

as a last resort before shipping the equipment to depot for maintenance.

4-4