TM 1-1520-238-T-7
11–313
11–77. 26 VAC EXCITATION XFMR 2 NO-GO AFT AVIONICS BAY –
11–77
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 1-1520-238-23
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. Detach P686. Check for 21 to 26 VAC at
P686–56.
Is voltage present?
YES
(ACA) Replace DASEC
(TM 1-1520-238-23).
(ACB) Go to step 3.
NO
Go to step 2.
2. Check for open between:
(ACA) P686–56 and (A323)TB2–1–F,
P686–55 and GS604–B.
(ACB) P686–56 and P694–9,
P686–55 and P964–10.
Does open exist?
YES
Repair open wire.
Go to paragraph 11–23.
NO
(ACA) Go to step 5.
(ACH) Go to step 4.
3. (ACB) Attach P686. Detach filter adapter A707.
Check for 21 to 26 VAC between A707–56 and
A707–55.
Is voltage present?
YES
Replace DASEC
(TM 1-1520-238-23).
NO
Replace filter adapter
(TM 1-1520-238-23).
4. (ACB) Attach P686. Detach filter adapter A707.
Check for open between:
A707–56 and P964–9,
A707–55 and P964–10.
Does open exist?
YES
Replace filter adapter
(TM 1-1520-238-23).
NO
Go to step 8.
5. (ACA) Detach wire from (A323)TB2–1–E. Check
for 21 to 26 VAC between wire end
(A323)TB2–1–E and GS1–B.
Is voltage present?
YES
Go to step 7.
NO
Go to step 6.
6. (ACA) Check for 115 VAC at (A323)TB2–1–B.
Is voltage present?
YES
Replace 26 VAC excitation
transformer
(TM 1-1520-238-23).
NO
Repair open wire between
(A323):
TB2–1–A and J5–B7.
Go to paragraph 11–23.
7. (ACA) Attach wire to (A323)TB2–1–E. Detach
P493, (A323): TB3–7–M and TB3–7–L. Check
for 21 to 26 VAC at P686–56.
Is voltage present?
YES
Go to step 12.
NO
Go to step 9.
