TM 1-1520-238-T-6
9–760
9–398. LOW RPM ROTOR AUDIO WARNING – IS NOT HEARD IN BOTH HEADSETS
9–398
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer
One person to assist
References:
TM 1-1520-238-23
TM 1-1520-238-T-4
WARNING
Turn off power before detaching or
attaching wires and connectors. High
current 28 VDC or 115 VAC is present.
Failure to do so could result in death or
serious injury.
1. Check for 28 VDC at (A76)J1-N.
Is voltage present?
YES
Go to step 2.
NO
Go to paragraph 9–263 to
torubleshoot circuit protection
system (dc emergency bus –
pilot station).
2. Check for open between:
P463-N and P49-14,
P49-16 and ground.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–395.
NO
Go to step 3.
3. Check for 0.6 to 0.8 VAC between P49-9 and
P49-10.
Is voltage present?
YES
Go to step 4.
NO
Go to step 5.
4. Check for open between:
P49-11 and P318-A1,
P49-24 and P318-A2.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–395.
NO
Replace engine out warning unit
(TM 1-1520-238-23).
5. Check for open between:
P49-9 and (A326)TB1-9-G,
P49-10 and (A326)TB1-9-M.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–395.
NO
Refer to TM 1-1520-238-T-4 to
troubleshoot drive system.
END OF TASK
