TM 1-1520-238-T-5
7–116
7–36.
ROTOR BRAKE – DOES NOT STOP ROTOR ROTATION
7–36
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer (2)
References:
TM 1-1520-238-T-6
TM 1-1520-238-23
Equipment Conditions:
Ref
Condition
TM 1-1520-238-23
Access provisions –
250R, 250L, 290R,
290L and L325 doors
open
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. On pilot power quadrant, set RTR BK switch to
BRAKE and PWR levers to OFF. Check for
28 VDC at P238–1.
Is voltage present?
YES
Go to step 2.
NO
Go to step 3.
2. Check for 90 9 ohms resistance between
(HP2):
J1–5 and J1–1.
Is resistance present?
YES
Repair open wire between
P238–5 and GS630–F.
Go to paragraph 7–21.
NO
Go to step 6.
3. Check for 28 VDC at P173–Z.
Is voltage present?
YES
Go to step 5.
NO
Go to step 4.
4. Check for 28 VDC at (A76)J1–n.
Is voltage present?
YES
Repair open wire between:
(A402)TB2–9–N and P463–n,
(A402)TB2–9–R and P173–Z,
or replace (A402)TB2–9.
Go to paragraph 7–21.
NO
Refer to TM 1-1520-238-T-6 to
troubleshoot circuit protection
system (dc emergency bus –
pilot station).
5. Set RTR BK switch to BRAKE and PWR levers
to OFF. Check for open between (A24): J1–Z
and J1–b.
Does open exist?
YES
Replace pilot power quadrant
(TM 1-1520-238-23).
NO
Repair open wire between
173–b and P238–1.
Go to paragraph 7–21.
6. Remove utility manifold rotor brake ON solenoid
(TM 1-1520-238-23). Check for open between
(HP2):
J1–1 and J9–D,
J1–5 and J9–A.
Does open exist?
YES
Replace utility hydraulic
manifold (TM 1-1520-238-23).
NO
Replace utility manifold rotor
brake ON solenoid
(TM 1-1520-238-23).
END OF TASK
