TM 1-1520-238-T-6
9–407
9–166. ECS L NOSE GRBX HTR CIRCUIT BREAKER (CB38) – DOES NOT STAY CLOSED
9–166
OR 115 VAC IS NOT PRESENT AT: P2-m, P2-n, P2-p
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-8
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 ELEC PWR panel, set BATT/EXT PWR
switch to EXT PWR.
Does ECS L NOSE GRBX HTR Circuit breaker
(CB38) stay closed?
YES
Go to step 4.
NO
Go to step 2.
2. Open CB38. Set BATT/EXT PWR switch to OFF.
Check for short between:
P2-m and ground,
P2-n and ground,
P2-p and ground.
Does short exist?
YES
Go to step 3.
NO
Refer to TM 1-1520-238-T-8 to
troubleshoot engine anti-ice.
3. Detach wire at CB38-A2, CB38-B2, and
CB38-C2. Check for short between:
P2-m and ground,
P2-n and ground,
P2-p and ground.
Does short exist?
YES
Repair shorted wire.
Go to paragraph 9–150.
NO
Replace ECS L NOSE GRBX
HTR circuit breaker (CB38)
(TM 1-1520-238-23).
4. Set BATT/EXT PWR switch to OFF. Check for
open between:
CB38-A1 and P3-G,
CB38-B1 and P3-H,
CB38-C1 and P3-J,
CB38-A2 and P2-m,
CB38-B2 and P2-n,
CB38-C2 and P2-p.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–150.
NO
Replace ECS L NOSE GRBX
HTR circuit breaker (CB38)
(TM 1-1520-238-23).
END OF TASK
