TM 55-1520-240-T 16-212          Change 24      16-5.6  LANDING GEAR SWITCH STATUS, READY TO FIRE, OR LANDING GEAR BYPASS LIGHTS DO NOT LIGHT DURING PRESS TO TEST (Continued)      16-5.6 DO ANY OF THE THREE LIGHTS ILLUMINATE DURING PRESS-TO-TEST? DISCONNECT PLUG 147P4 FROM REMOTE BYPASS SWITCH PANEL.  IS 28 VDC PRESENT ON PIN B? IS GROUND PRESENT ON CONNECTOR 147P4 PIN A? LOCATE AND REPAIR FAULT ON REMOTE BYPASS SWITCH PANEL. DOES LDG GEAR BYPASS LIGHT ILLUMINATE DURING PRESS-TO-TEST? OPEN EAPS/MEAPS CB PANEL.  CHECK FOR CON- TINUITY FROM DCDU CB CIRCUIT SIDE TO PLUG 147P4 PIN B. IS CONTINUITY PRESENT? IS 28VDC PRESENT ON BUS SIDE OF DCDU CIRCUIT BREAKER? LOCATE AND REPAIR FAULT IN WIRE W668- 6D289B20N. REPAIR FAULTY WIRING BETWEEN DCDU AND CONNECTOR 147P4 PIN B. REPAIR/REPLACE FAULTY WIRING/ COMPONENT ON LDG GEAR REMOTE BYPASS PANEL. NO REPLACE LAMP IN READY TO FIRE LIGHT AND PRESS TO TEST.   DOES LAMP ILLUMINATE? DOES LDG GEAR REMOTE BYPASS SWITCH STATUS LIGHT ILLUMINATE DURING PRESS-TO- TEST? REMOVE AND REPLACE FAULTY DCDU CIRCUIT BREAKER. TROUBLESHOOT NO. 1 DC BUS.  (TASK 9-1.4) REPLACE LAMP AND PRESS TO TEST.  DOES LAMP ILLUMINATE? REPLACE LAMP AND PRESS TO TEST.  DOES LAMP ILLUMINATE? LOCATE AND REPAIR FAULT IN REMOTE BYPASS SWITCH PANEL. YES YES NO NO FAULT CORRECTED. YES YES YES YES YES YES NO NO NO NO NO YES NO NO YES REPAIR/REPLACE FAULTY WIRING/COMPONENT ON LDG GEAR REMOTE BYPASS PANEL. FAULT CORRECTED. END OF TASK