TM 55-1510-219-10 NOTE CDU  BAT  indicator  will  illuminate for 12 seconds in alignment State "8"   (about   5   minutes   after   turn- on).  This is normal and indicates a  battery  test  is  in  progress.    No corrective action is required. NOTE Ground operation on battery power should not exceed 5 minutes. (e) To determine corrective action: (Monitor  CDU  displays  while  rotating  the  CDU  selector switch.) 1. If  displays  are  frozen  (do  not change  while  data  selector  is being rotated) problem is normally     in     the     navigation unit. 2. If   displays   respond   normally to     the     data     selector,     the problem  is  normally  absence of 115V AC power to INS. (f) For    corrective    action:    Check    to assure  proper  settings  of  following  switches  and  circuit breakers essential to INS operation: 1 Overhead  circuit  breaker panel (fig.  2-26): Circuit breakers In: 1. *        AVIONICS    MASTER CONTR 2. * INS CONTROL 3. *        AVIONICS    MASTER PWR #1 4. *        AVIONICS    MASTER PWR #2 2 Overhead   control   panel   (fig. 2-18): INVERTER No.  1 or INVERTER No.2 switch On (either). 3 Mission  control  panel  (fig.    4- 1): 1. 3-phase    AC  BUS  switch On. 2. INS POWER & AC CONT circuit breakers - In. 4 Mission AC/DC power cabinet: INS PWR circuit breaker In. Table 3-4.  Action Codes and Recommended Action NOTE CDU BAT indicator should extinguish  after  above  corrective action.    If  it  remains  illuminated, INS    will    eventually    shut    down when battery voltage drops below approximately 19VDC. Flight crew should prepare for shutdown. (3)    Malfunction   indications   and   procedures. Table 3-2 details the procedure for a Malfunction Code Check.        Table    3-3    lists    a    number    of    malfunction indications which occur under given modes of operation. Follow procedure given.  Table 3-4 details action codes and  recommended  action.    Table  3-5  lists  failed  test symptoms   by   malfunction   codes   and   lists   codes   for recommended actions. (4)    Read    computer    memory    through    CDU (look routine). 1. WYPT CHG key Press. 2. Keys Enter "99".  Note FROM TO displays "99". 3. INSERT/ADVANCE pushbutton Press. 4. Data selector LIL WYPT. 5. CDU   Enter   "N"   followed   by octal address of desired (even numbered) memory location. 3-70