TM 55-1520-240-T 18-1.2    GLOBAL POSITIONING SYSTEM VISUAL CHECK 18-1.2 INITIAL SETUP References: Applicable Configurations TM 55-1520-240-23 All Equipment Condition: Tools: TM 55-1520-240-23: Electrical Repairer's Tool Kit, Battery Disconnected NSN 5180-00-323-4915 Electrical Power Off No. 2 Access Door (Tunnel Cover) Materials: Open None Personnel Required: 68F10 Aircraft Electrician TASK RESULT 1.  Check GPS CDU (1). Loosen Dzus fasteners and check connector of GPS  CDU1).  If  connector  is  loose  or  damaged  tighten  or replace  it  as  required.    If  wiring  to  connector  is  loose  or damaged, tighten, repair, or replace it as required. If display screen is damaged in any way replace CDU (1). If knobs are loose    or    broken    tighten    or    replace    as    required.    If pushbuttons are damaged replace CDU (1).  Reinstall CDU (1) in the canted console tightening the Dzus fasteners. 2.  Check GPS Alert Light Indicator (2). If indicator (2) is loose or damaged tighten or replace as required. 3.  Check GPS Zeroize Switch/Cover (3). If switch or cover (3) is loose or damaged tighten or replace as required.  If wiring to switch is loose or broken tighten, repair, or replace as required. 4.  Check GPSIDOP SEL Indicator (4). If indicator lens (4) is damaged replace. 5.  Check GPS RCVR and GPS CONT Circuit If breaker(s) (5) is loose or damaged tighten or Breakers (5).  replace as required.  If wiring to breaker(s) is loose or broken tighten, repair, or replace as required. 6.  Check GPS Radio Receiver R-2400( )A (6). If receiver (6) is loose or damaged tighten or replace as required.  If connectors to the receiver are loose or  damaged  tighten  or  replace  as  required.    If  wiring  or cables to receiver are loose or damaged tighten, repair, or replace as required. TASK RESULT 7.  Check GPS Data Loader Receptacle (7). If receptacle (7) is loose or damaged tighten or replace as required.    If  pushbutton  is  loose  or  damaged  replace  Data Loader  Receptacle.    If  the  connector  to  the  receptacle  is loose or damaged tighten or replace as required  If wiring to the connector is loose or damaged tighten, repair, or replace as required. 8.  Check KYK/GPS Fill Connector (J1) (8). If  connector  (8)  is  loose  or  damaged  tighten  or  replace  as required.    If  wiring  to  the  connector  is  loose  or  damaged tighten, repair, or replace as required. 9.  Check INIT Load Push Button Switch (9). If  switch  (9)  is  loose  or  damaged  tighten  or  replace  as required.    If  wiring  to  the  connector  is  loose  or  damaged tighten, repair, or replace as required. 10.Check Load Status LED (10). If  LED  (10)  is  loose  or  damaged  tighten  or  replace  as required. 11.Check AE-4 Antenna Amplifier (11). If  amplifier  (11)  is  loose  or  damaged  tighten  or  replace  as required.      If   connectors   to   the   amplifier   are   loose   or damaged   tighten   or   replace   as   required.      If   cables   to amplifier J1 and J3 are loose or damaged tighten, repair, or replace  as  required.    If  cable  to  J2  is  loose  tighten,  if damaged  replace  ONLY,  DO  NOT  REPAIR  THIS  LOW- LOSS CABLE GOING TO GPS ANTENNA (12). 12.Check GPS Antenna (13). If  antenna  (13)  is  loose  or  damaged  tighten  or  replace  as required.  If cable (12) to antenna is loose or broken tighten or replace as required.  DO NOT REPAIR THIS CABLE. FOLLOW-ON MAINTENANCE: Close No.  2 Access Door (Tunnel Cover) GO TO NEXT PAGE 18-12  Change 18