TM  55-1520-240-T 15-7.3 APU TESTER OPERATION 15-7.3 References: TM  55-1520-240-23 TM  55-4920-431-13 Equipment   Condition: TM  55-1520-240-23: Battery   Connected External  Electrical  Power  Off INITIAL  SETUP Applicable Configurations: All Tools: Electrical  Repairer’s  Tool  Kit. NSN  5180-00-329-4915 APU  Tester  161226-200 Materials: None Personnel   Required: Aircraft    Electrician TASK RESULT TASK RESULT 1. 2. 3. 4. 5. 6. 7. 8. 9. Turn pressure equalizer knob to OPEN. Open case. Remove P1, P2 and P5 harnesses. Inspect equipment for any physical damage. Zero  meters. Connect harnesses to the applicable J1, J2 and J5 connectors on test set. Remove 136P1 and 136P2 from ESU and connect to the corresponding cable connectors of harnesses. Connect the remaining harness plugs to J1 and J2 of ESU. Perform test in accordance with applicable  task. Pressure on cover is released. NOTE During tests, leave BLEED AIR OPEN/CLOSE switch, MAX. AIR switch, and ECONO AIR switch in down  position. Repair or replace as required. 10. 11. 12. 13. Wiring  should  be  similar  to  that  shown in  accompanying  diagram. After  completion  of  task,  return  all tester switches to DOWN position. Disconnect harnesses and stow in cover. Close cover and rotate pressure equalizer knob to CLOSE. Report  any  tester  operation problems on proper form as described  in  DA  Pam  738-751. Tester is secured. FOLLOW-ON  MAINTENANCE: TM55-4920-431-13 REFER TO TASK BEING PERFORMED. GO TO NEXT PAGE 15-142 Change 8