TM 1-1520-238-T-4 6–165 6–82. LOW RPM ROTOR INDICATORS – REMAIN LIGHTED ABOVE 93% N_R 6–82 Tools: Nomenclature Part Number Tool Kit, Aircraft SC518099CLA01 Mechanic’s Tool Kit, Electrical SC518099CLA06 Repairer’s Multimeter, Digital AN/PSM-45 Personnel Required: 67R Attack Helicopter Repairer 68F Aircraft Electrician References: TM 1-1520-238-T-6 TM 1-1520-238-23 Equipment Conditions: Ref Condition TM 1-1520-238-23 Access provisions – L140 fairing and L325, T250L, T250R, T290L, T290R and T325 access 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. Check rotor N_R indicator for rpm indication. Does N_R indicator continue to operate correctly? YES Go to step 2. NO Go to step 3. 2. Detach P49. Does LOW RPM ROTOR indicators remain lit? YES Go to step 4. NO Go to step 5. 3. Check for open between J755–23 and J755–22. Does open exist? YES Replace magnetic pickup and isolation transformer (TM 1-1520-238-23). NO Repair open wire between: P755–22 and (A326)TB1–9–F, P755–23 and (A326)TB1–9–L. 4. Detach P20 and P31. Does LOW RPM ROTOR indicators remain lit? YES Refer to TM 1-1520-238-T-6 to troubleshoot the pilot and CPG caution/warning system. NO Go to step 6. 5. Check for open between: (A326)TB1–9–G and P49–9, (A326)TB1–9–M and P49–10. Does open exist? YES Repair open wire. Go to paragraph 6–81. NO Replace engine out warning unit (TM 1-1520-238-23). 6. Attach P31 and detach (A326)TB1–10–F. Check for short between P20–X and ground. Does short exist? YES Repair shorted wire between P20–X and P49–18. Go to paragraph 6–81. NO Repair shorted wire between P31–X and P49–18. Go to paragraph 6–81. END OF TASK