TM 1-1510-225-10 3C-52 5.   Briefly  press   WX/C  push  button  and slide    TGT    ALERT    control    to     ON.   Verify  that  the  letter  T  in  a  red  box appears in the target alert field. 6.   Press  TEST push button and observe that   when   the   test   pattern   display crosses     the     centerline,     the     T     is replaced    by    a    flashing    TGT    label.   Slide  TGT  ALERT control to   OFF to disable the function. 7.   Verify that 100 (nm) is displayed in the upper  right-hand  corner  and  that  the first four range marks are labeled with the correct numerics. 8.   Slide  AZ MK control to  ON  and  verify that  azimuth  marks  are  displayed  in cyan  at  30  intervals.    Slide   AZ  MK control   to    OFF   to   remove   azimuth marks. 9.   Briefly   press    WX/C   push   button   to erase     display,     press     TEST push button. After approximately 2 seconds,    momentarily    press    FRZ and    verify    that    the    1    2    3    display beneath the color bar is replaced by a flashing  FRZ  label.  Verify  that  only  a portion of the test pattern is displayed and    there    is    no    further    updating.   Momentarily  press   FRZ  push  button and    verify    that    the    display    begins updating  starting  at  the  current  scan position. 10.   Press  10 (nm) range push button and verify that the test pattern is momentarily blanked and then restored to the previous display. 11.   Briefly  press   WX/C  push  button  and verify  that  WX  displays  in  the  Mode field  and  10  displays  as  the  selected range.  Verify correct range numerics. 12.   Press    each    range    push    button    in succession (25 /  50/  100 /  200 /  300) and verify that range numerics change appropriately with each selection. 13.   Briefly  press   WX/C  push  button  and verify   that   CYC   is   displayed   in   the Mode field. 14.   Rotate GAI N     control     just     out     of PRESET  and verily that 1 2 3 remains in the auxiliary field. 15.   Briefly  press   WX/C  push  button  and verify   that   WX   is   displayed   in   the mode field and that VAR replaces 1 2 3 in auxiliary field. 16.   Briefly   press   MAP  push  button  and verify   that   MAP   is   displayed   in   the Mode field.  Verify that the color of the range   marks   and   alphanumerics   is green. 17.   Briefly   press   STBY   push   button   to return  radar  to  non-transmitting state.   Return GAIN control to PRESET. (4)   Fault     Displays.          Display     colors     are continuously  monitored  by  the  color  bar  and  1  2  3 legend in the auxiliary field.  If a fault causes a change to unfamiliar colors, the severity level denoted by the faulty color(s) is directly coded by the 1 2 3 legend. NOTE If   the   fault   was   of   transient   nature,   the system may operate satisfactorily. Other  circuits  continuously  monitor  performance and    loading    of    system    power    supplies.        A    fault resulting  in  power  supply  operation  outside  of  preset limits   will   cause   the   system   to   shut   down   and   the display   will   be   blank.      Should   this   occur,   use   the following procedure to recycle the system: 1.   Rotate INT / OFF control to OFF. 2.   Verify  aircraft  radar  circuit  breaker  is on. 3.   After a few seconds, rotate  INT / OFF control  to  midpoint  and  press    TEST push button. (5)   Ground     Mapping.          Ground     mapping operation   is   selected   by   pressing   the    MAP   push button.    Turn  the   TILT  control  down  until  the  desired amount of terrain is displayed.  The degree of down tilt will  depend  upon  the  type  of  terrain,  aircraft  altitude, and selected range. For    the    low    ranges    (10,    25,    and    50),    the transmitter  pulse  width  is  narrowed  and  the  receiver bandwidth is widened to enhance the identification of small targets.