TM 1-1270-476-30
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CHAPTER 3
TROUBLESHOOTING
Subject
Para
Page
Fault Detection/Location System (FD/LS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1
3-1
Line Replaceable Unit (LRU)/Shop Replaceable Unit (SRU) Troubleshooting . . . . . .
3-2
3-1
Corrective Action Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3
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Malfunction Corrective Action Printout Cross-Reference . . . . . . . . . . . . . . . . . . . . . .
3-4
3-1
OVERVIEW
This chapter describes aviation intermediate maintenance (AVIM) troubleshooting methods and
references troubleshooting procedures using the helicopter fault detection/location system (FD/LS) and
rear area automatic test equipment. A detailed description of the overall troubleshooting methodology is
contained in TM 1-1270-476-T.
3-1. FAULT DETECTION/LOCATION SYSTEM (FD/LS)
The TADS system FD/LS general description and maintenance operational check (MOC)
procedures are in TM 1-1270-476-T.
3-2. LINE REPLACEABLE UNIT (LRU)/SHOP REPLACEABLE UNIT (SRU) TROUBLESHOOTING
a.
Both LRUs and SRUs are tested at AVIM by computer test programs, that are run on automatic
test equipment (ATE). An LRU fault is located to an SRU, to a single component, or to a group of
components. An SRU fault is located to a shop replaceable subassembly, to a single component or to
group of components. A test program and all necessary adapters are referred to as a test program set
(TPS).
b.
The EETF incorporates the TADS/PNVS Augmentation Equipment. The LRU and SRU test
procedures are contained in test programs and are displayed on the cathode ray tube (CRT). Upon
completion of the tests, a computer printout provides corrective action information for the malfunctioning
LRU or SRU.
3-3. CORRECTIVE ACTION INFORMATION
Corrective action includes replacing a faulty SRU, subassembly, or component(s), repairing a
faulty continuity path, and/or alining and adjusting the failed LRU or SRU. After corrective action is
performed, the repaired LRU or SRU is returned to the EETF for acceptance testing.
3-4. MALFUNCTION CORRECTIVE ACTION PRINTOUT CROSS-REFEREMCE
In many instances the EETF malfunction corrective action printout provides instructions to replace
a failed component that is beyond the capability of AVIM. In those cases, request higher level of
maintenance assistance. To provide easy access to replacement tasks, the table below lists the
corrective action as it appears in the EETF printout. Opposite each entry is the corrective action task as
it appears in chapter 4.
