TM 55-1520-240-T 9-18.3 MASTER CAUTION LIGHTS OPERATIONAL CHECK (Continued) 9-18.3 TASK RESULT 1. Check that LIGHTING CAUTION PNL circuit breaker If CAUTION PNL circuit breaker (1) is open, close it.  If it (1) is closed. opens again, go to task 9-18.4. 2. Check pilot's and copilot's MASTER CAUTION lights Both pilot's and copilots MASTER CAUTION lights (2 and 3) (2 and 3) and master caution panel capsules. and some capsules on master caution panel (4) shall come on  bright.    If  caution  capsules  do  not  come  on,  go  to  task 9-18.5 or 9-18.5.1.  If pilots or copilot's MASTER CAUTION lights do not come on, go to task 9-18.6.  If master caution panel capsules and MASTER CAUTION lights come on dim, go to task 9-18.7.  If one MASTER CAUTION light comes on dim and one comes on bright, go to task 9-18.12.  Without 74 if all capsules in rows 4, 7, and 12 are on or if all capsules in remaining rows are on, replace master caution panel.   With 74 if all capsules in rows 4, 7, 12, and 16 are on or if all capsules in remaining rows are on, replace master caution panel.  Repeat task 9-13.3. 3. Press and release pilot's MASTER CAUTION light (2). Both pilot's and copilot's MASTER CAUTION lights (2 and 3) shall go out, lighted capsules on master caution panel (4) shall remain on.  If pilot's and copilot's master caution lights remain on, go to task 9-18.8. 4. Set and hold CAUTION LIGHTS (or LT) TEST switch(5) All capsules on master caution panel (4) and  MASTER to TEST. CAUTION lights (2 and 3) shall come on bright.  If lights not come on, go to task 9-18.8. 5. Release CAUTION LIGHTS (or LT) TEST switch (5) to Some capsules on master caution panel (4) shall go out.  If OFF. none go out, replace CAUTION LIGHTS (or LT) TEST switch. 6. Open, then dose LIGHTING CAUTION PNL circuit Both pilot and copilot MASTER CAUTION lights (2 and 3) and some capsules on master caution panel (4) shall come on bright.  If pilot's or copilot’s MASTER CAUTION lights do not come on, go to task 9-18.6. 7. Momentarily set CAUTION LIGHTS (or LT) DIM/ Lighted capsules on master caution panel (4) and both BRIGHT switch (6) to DIM. MASTER CAUTION lights (2 and 3) shall dim, if not, go to task 9-18.10. 8. Momentarily set CAUTION LIGHTS (or LT) DIM/ Lighted capsules on master caution panel (4) and both BRIGHT switch (6) to BRIGHT. MASTER CAUTION lights (2 and 3) shall get bright.  If not, go to task 9-18.7. 9. Momentarily set CAUTION LIGHTS (or LT) DIM/BRIGHT switch (6) to DIM. 10. Check that DOME SELECT or DOME switch (7) is at If switch (7) is not at OFF, set it to OFF. OFF. 11. Check that LIGHTING COCKPIT DOME circuit breaker If circuit breaker (8) is not dosed, close it.  If it opens again, (8) is closed. go to task 9-14.3. TASK RESULT 12. Set DOME SELECT switch (7) to WHITE.   Lighted capsules on master caution panel (4) and both MASTER CAUTION lights (2 and 3) shall come on bright, if not go to task 9-18.11. 13. Press and release copilots MASTER CAUTION light Both pilot's and copilot’s MASTER CAUTION lights (2 and 3) (3). shall go out.  If not, go to task 9-18.8. 14. Set DOME SELECT switch (7) to OFF.   Lighted capsules on master caution panel (4) and both MASTER CAUTION lights (2 and 3) shall remain bright FOLLOW-ON MAINTENANCE: TM 55-1520-240-22: Battery disconnected. Electrical power off. Hydraulic power off. END OF TASK Change 19  9-325