TM 1–1520–238–T–2
1–5
1–7.
TROUBLESHOOTING EXAMPLES (cont)
1–7
(6) Refer to TM 1–1520–238–T–3 and read HOW TO USE THIS VOLUME and chapter 1 to become
familiar with the volume.
(7) In TM 1–1520–238–T–3, go to chapter 2 (Air Data System (ADS) Multiplex Read Codes).
(8) Find the symptom in the master failure symptom index. (The Refer to paragraph column specifies
para 2–1.)
(9) Go to paragraph 2–1 and enter the specified memory location code. (For this example, assume a FAIL
occurs at para 2–2.)
(10) Troubleshoot using the system manual (TM 9–1230–476–20–2) as instructed in paragraph 2–2.
b. Example Using System Volume.
(1) Assume the following failure symptom is known – Pilot TGT indicator vertical scales or digital readouts
do not indicate ambient temperature (5).
(2) Find the failure symptom in the master failure symptom index Table 2–1. (The Reference column
specifies TM 1–1520–238–T–5, and the MOC column specifies ENGINE INSTRUMENTS.)
(3) Refer to TM 1–1520–238–T–5 and read HOW TO USE THIS VOLUME and chapter 1 to become
familiar with the volume.
(4) Go to ENGINE INSTRUMENTS – MAINTENANCE OPERATIONAL CHECK (para 8–10).
(5) Perform the MOC. Step m. in the Task column instructs you to rotate DIM control to midposition and
check all pilot engine instruments. The Result column directs you to a FIP if the failure symptom in step (1) of this
example still exists.
(6) Perform the indicated FIP to correct problem.
Section III.
DISPLAY SYMBOLOGY DATA
1–8.
DATA PRESENTATION
1–8
Often you will track a fault by analyzing the display symbology and readouts on the pilot video display unit (VDU)
and CPG heads out display (HOD). The following figures help you locate precisely where a piece of symbology
appears on the VDU and the HOD.
1–9.
DATA ARRANGEMENT
1–9
The figures provide symbol nomenclature, applicable subsystem in parentheses, and the item number in the
corresponding figure.
a. Pilot helmet display unit (HDU) and VDU display symbology data is provided in figure 1–1.
b. CPG HDU and HOD symbology data is provided in figure 1–2.
