TM 1-1520-238-T-7 Change 4 11–247 11–31. ASE BUCS CIRCUIT BREAKER – DOES NOT STAY CLOSED 11–31 Tools: Nomenclature Part Number Tool Kit, Electrical SC518099CLA06 Repairer’s Multimeter, Digital AN/PSM-45 Personnel Required: 68X Armament/Electrical Systems Repairer References: TM 1-1520-238-T-6 TM 1-1520-238-23 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. Open ASE BUCS circuit breaker. Check for short between (A76)P1–33 and ground. Does short exist? YES Refer to TM 1-1520-238-T-6 to troubleshoot circuit protection system (dc essential bus 3 – pilot station). NO Go to step 2. 2. Detach P431 and P441. Check for short between (A402)J27–A10 and ground. Does short exist? YES Repair shorted wire between: (A402)J27–A10 and (A402)TB2–3–B, (A402)J1–33 and (A402)TB2–3–A, (A402)J24–B2 and (A402)TB2–3–C. Go to paragraph 11–23. NO Go to step 3. 3. Check for short between P431–A10 and ground. Does short exist? YES Go to step 4. NO Go to step 5. 4. Detach P682 and P686. Check for short between P686–60 and ground. Does short exist? YES Go to step 7. NO (ACA) Replace DASEC (TM 1-1520-238-23). (ACB) Go to step 6. 5. Detach P686. Check for short between P441–B2 and ground. Does short exist? YES Go to step 8. NO (ACA) Replace DASEC (TM 1-1520-238-23). (ACB) Go to step 6. 6. (ACB)Attach P686. Detach filter adapter A707. Check for short between A707–60 and ground. Does short exist? YES Replace filter adapter (TM 1-1520-238-23). NO Replace DASEC (TM 1-1520-238-23). 7. Detach P493 and P499. Check for short between P686–60 and ground. Does short exist? YES Repair shorted wire between: P493–B12 and J415 SP1, P431–A10 and J415 SP1, P499–A3 and J417 SP1, P686–60 and J415 SP1, P686–59 and J417 SP1, J417–SP1 and J415 SP1. Go to paragraph 11–23. NO Go to step 9.