CSP-HMI-3MD Helicopters, Inc.
MAINTENANCE MANUAL
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Table 109. Quad Digital Indicator (Torque, TOT, OAT, N
1
) Troubleshooting (Cont.)
Symptom Corrective ActionProbable Trouble
N
1
Rpm indicator fails to operate. No
readings or intermittent readings
Defective indicator Remove and replace indicator.
Defective tach generator Remove and replace tach
generator.
Loose wiring, disconnected
connector or defective ground
terminal
Check continuity through wiring and
connector. Repair as necessary.
11. Quad Digital Indicator (Oil Temp, Oil Press, Vdc, Amp)
Table 110. Quad Digital Indicator (Oil Temp, Oil Press, Vdc, Amp) Troubleshooting
Symptom Probable Trouble Corrective Action
Oil Temp
Pressure indicator fails to operate.
No readings or intermittent readings
Defective indicator Remove and replace indicator.
Loose wiring, disconnected
connector or defective ground
terminal
Check continuity through wiring and
connector. Repair as necessary.
No out put from oil pressure
transducer
Defective transducer Replace transducer (Ref. Engine
Torque and/or Oil Pressure
Transducer Replacement).
Oil Press
Oil temperature fails to operated.
No reading or intermittent reading
Open circuit in oil temperature bulb Remove and replace oil
temperature bulb.
Defective wiring Repair as necessary.
Table 111. Input/Output Signals − Autronics EPO Warning Control Unit
Input Output
Connector
J21 Pin
Name Signal or Control Connector
J22 Pin
(P19)
Name Signal or Control
A N
1
tach gen AC voltage, 38.5 Hz,
or less
F Eng out light
flasher and
audible warning
horn
Pulsating 28 Vdc with
3 − 5 Hz flash rate,
0.2A max., 28 Vdc
present for min. 25%
− max. 75% of flash
rate period.