TM 1–1520–238–T–2
1–4
1–6.
FUNCTION OF EACH VOLUME OF THE MANUAL (cont)
1–6
h. TM 1–1520–238–T–8, Aviation Unit and Intermediate Troubleshooting Manual. TM 1–1520–238–T–8
contains system location and description, theory of operation, ECLC index, power up/power down procedures,
MOCs, wiring interconnect diagrams, FIPs and FD/LS NO–GO FIPs. The following systems are covered in this
volume:
Utility.
Environmental Control.
Hoists and Winches (not applicable).
Auxiliary Power Unit.
Mission Equipment.
i. TM 1–1520–238–T–9, Theory of Operation.
TM 1–1520–238–T–9 contains description and theory of
operation for each aircraft system. This information includes signal flow diagrams for major system functions and
explanatory text with the appropriate signal name for each input or output. This information can be used to isolate
unanticipated faults for failure symptoms or related data which do not exist.
j. TM 1–1520–238–T–10, Wiring Diagrams.
TM 1–1520–238–T–10 provides point–to–point wiring for
each aircraft system. The diagrams show LRUs, cable interfaces, splices, shielding, ground studs, etc. Each cable
location and connection can be found in the wire harness location and routing diagrams. This volume also
contains connector end view diagrams and a symbol chart for the various wiring diagram symbols used.
k. Summary.
By using these volumes, you will be able to perform inclusive troubleshooting on the
helicopter. TM 1–1520–238–T–2 directs you to the appropriate volume when you know the failure symptom.
TM 1–1520–238–T–1, and TM 1–1520–238–T–3 through TM 1–1520–238–T–8 aid you in isolating faults and
making repairs. TM 1–1520–238–T–9 and TM 1–1520–238–T–10 give you additional information to help you
troubleshoot the helicopter.
1–7.
TROUBLESHOOTING EXAMPLES
1–7
The following troubleshooting examples illustrate how the volumes should be used together to locate and isolate
faults.
a. Example Using TM 1–1520–238–T–3 Multiplex (MUX) Read Code Volume.
(1) Assume the following failure symptom is known – ADS INDICATOR LIGHTS (PILOT ANTI ICE PANEL:
PITOT ICE DET AD SNSR SWITCH SET TO OFF).
(2) Find the failure symptom in the master failure symptom index Table 2–1., TM 1–1520–238–T–2. (The
Reference column specifies TM 9–1230–476–20–2, and the MOC column specifies AIR DATA SYSTEM.)
(3) Refer to TM 9–1230–476–20–2 and read HOW TO USE THIS MANUAL and chapter 1 to become
familiar with the manual.
(4) Go to the MOC (para 3–14), AIR DATA SYSTEM – MAINTENANCE OPERATIONAL CHECK.
(5) Perform the MOC in paragraph 3–14. Step b. in the Task column instructs you to verify PITOT ICE
DET AD SNSR switch is OFF and CPG AUX/ANTI–ICE panel ADSS switch is set to ADSS position. The Result
column directs you to TM 1–1520–238–T–3 to perform troubleshooting. Then if no fault is found, go to the
paragraph indicated.
