TM 55-1520-240-T 9-1.4 DC POWER SYSTEM OPERATIONAL CHECK (Continued) 9-1.4 TASK RESULT 11. Open NO. 1 REV CUR CO circuit breaker (6). NO. 1 RECT OFF (Without 74) RECT 1 (With  74) capsule (16) shall come on.  If it does not, replace NO. 1 reverse current cutout relay. 12. Turn top and bottom anti collision lights ON.  Refer to Both top and bottom anti collision lights shall flash.  If they task 9-6.3. do not, go to task 9-1.12. 13. Turn overhead panel lights ON. Overhead panel lights shall come on.  If they do not, go to task 9-1.13. 14. Close NO. 1 REV CUR CO circuit breaker (6).  Open NO. 1 RECT OFF (Without 74) RECT 1 (With  74) capsule (16) shall go out.  NO. 2  RECT OFF (Without 74)  RECT 2 (With 74) capsule (17) shall come on.  If it does not, replace NO. 2 reverse current cutout relay. 15. Check overhead panel lights.    Overhead panel lights shall still be on.  If they are out, go to task 9-1.14. 16. Check anti collision lights. Anti collision lights shall still be on.  If they are not, go to task 9-1.15. 17. Turn off overhead panel lights. 18. Close NO. 2 REV CUR CO circuit breaker (13). NO. 2 RECT OFF (Without 74) RECT 2 (With  74) capsule (17) shall go out. 19. Open NO. 1 REV CUR CO and NO. 2 REV CUR CO NO. 1 and NO. 2 RECT OFF (Without 74) RECT 1 and circuit breakers (6 and 13). RECT 2 (With  74) capsules (16 and 17) shall come on. 20. Turn cabin and ramp white lights ON. Cabin and ramp white lights shall come on.  If they do not, go to task 9-1.16. 21. Close NO. 1 REV CUR CO and NO. 2 REV CUR CO NO. 1 and NO. 2 RECT OFF (Without 74) RECT 1 and circuit breakers (6 and 13). RECT 2 (With  74) capsule (16 and 17) shall go out. 22. Disconnect electrical connector (27) from battery (28). 23. Check cabin and ramp white lights. Cabin and ramp white lights shall stay on.  If they are not on, go to task 9-1.20. 23.1  Connect electrical connector (27) to battery (28). 24. Turn off cabin and ramp white lights.   Use CAB & RAMP LT switch.  Refer to task 9-15.3. NOTE Steps 25 through 27 can only be performed with an external 28VDC power source. TASK RESULT 25. Connect external 28VDC power source to receptacle NO. 1 and NO. 2 RECT OFF (Without 74) RECT 1 and (25).  Turn on power supply. RECT 2 (With  74) capsules (16 and 17) shall come on.  EXT PWR capsule (26) shall come on.  If capsule (16 or 17) is out, go to task 9-1.17.  If capsule (26) does not come on, go to task 9-1.18.  EXT PWR CONT circuit breaker (5) shall stay closed.  If it does not, go to task 9-1.21. 26. Check anti collision lights. Anticollision lights shall still be on.  If they are not, go to task 9-1.19. 27. Turn off and disconnect external 28VDC power. NO. 1 and NO. 2 RECT OFF (Without 74) RECT 1 and RECT 2 (With  74) capsules (16 and 17) shall go out.  EXT PWR capsule (26) shall go out. If any capsule (16, 17, or 26) is still on, replace external power control relay. 28. Turn off anti collision lights. 29. Shutdown apu.  Refer to task 15-1.4. FOLLOW-ON MAINTENANCE: None GO TO NEXT PAGE 9-12  Change 19