TM 1-1520-238-T-7
11–310
11–76.
26 VAC EXCITATION XFMR 1 NO-GO AFT AVIONICS BAY –
11–76
APPEARS ON HOD
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-T-6
TM 1-1520-238-23
Equipment Conditions:
Ref
Condition
TM 1-1520-238-23
Access provisions –
R295 door 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. Check for 21 to 26 VAC between P688–68 and
P688–69.
Is voltage present?
YES
(ACA) Replace DASEC
(TM 1-1520-238-23).
(ACB) Go to step 4.
NO
(ACA) Go to step 5.
(ACB) Go to step 2.
2. (ACB) Check for open between:
P688–69 and P693–9,
P688–68 and P693–10.
Does open exist?
YES
Repair open wire.
Go to paragraph 11–23.
NO
Go to step 3.
3. Check for open through pins A708–68 and
A708–69.
Does open exist?
YES
Replace filter adapter
(TM 1-1520-238-23).
NO
Go to step 6.
4. (ACB) Attach P688. Detach filter adapter A708.
Check for 21 to 26 VAC between A708–68 and
A708–69.
Is voltage present?
YES
Replace DASEC
(TM 1-1520-238-23).
NO
Replace filter adapter
(TM 1-1520-238-23).
5. (ACA) Check for open between:
P688–69 and (A323)TB2–1–K,
P688–68 and GS604–A.
Does open exist?
YES
Repair open wire.
Go to paragraph 11–23.
NO
Go to step 9.
6. Check for 115 VAC at P692–A.
Is voltage present?
YES
Go to step 8.
NO
Go to step 7.
7. Check for open between:
P692–A and (A402)J1–54,
P692–B and GS433–G.
Does open exist?
YES
Repair open wire.
Go to paragraph 11–23.
NO
Refer toTM 1-1520-238-T-6 to
troubleshoot circuit protection
system (ac essential bus 1 –
pilot station).
