TM 1-1510-225-10 3B-180 (4)   Range    Mark    Numerics.      Five   labeled range  marks  are  displayed  on  each  range.    The  fifth range   mark   label   is   larger   serving   to   identify   the selected   range.      Range   and   azimuth   marks   and numerics   are   displayed   in   cyan   for   WX,   CYC,   and TEST and in green for MAP. d.  Operation. To   prevent   electromagnetic   radiation   in ramp,   terminal,   taxiway,   or   other   areas occupied by personnel, operate radar only in standby mode. CAUTION Do    not    operate    radar    system,    even    in standby   mode,   without   115-Vac,    400-Hz  power  applied  to  the  system.    Without  ac power,    the    receiver-transmitter    cooling blower will not operate, which could result in circuit damage and/or automatic shutdown. (1)   Before    Turn    On.        Place    the    system controls   in   the   following   positions   before   applying power from the aircraft electrical system: 1.   INT    /    OFF    –    OFF    (fully    counter- clockwise in detent) 2.   GAIN     –     PRESET (fully counter- clockwise in detent) 3.   TILT – ±10 (fully clockwise) 4.   STAB – ON 5.   TGT ALRT – OFF 6.   AZ MK – OFF (2)   Precautionary Procedures. To be performed If the radar system is to be operated in any mode other than STBY or TEST  while the aircraft is on the ground: 1.   Direct    nose    of    aircraft    such    that antenna  scan  sector  is  free  of  large metallic  objects  such  as  hangars  or other aircraft for a distance of 100 feet (30    meters)    and    tilt    antenna    fully upwards. 2.   Avoid    operation    during    refueling    of aircraft  or  other  refueling  operations within 100 feet (30 meters). 3.   Avoid operation if personnel are standing too close in the 270° forward sector of the aircraft. (3)   Self-Test   Displays.      A   distinctive   test pattern    is    displayed    when    the    TEST    function    is selected.  The following procedures may be performed to   verify   the   operational   status   of   the   entire   radar system. 1.   Verify    that    the    preliminary    control settings  have  been  made  and    rotate INT / OFF control to mid-point to turn system    on.        Verify    that    STBY    is displayed in Mode field and that 100 is displayed as selected range. 2.   Press   WX/C   push   button   and   verify that WAIT is displayed in Mode field. NOTE A time delay circuit prevents the transmitter   from   operating   and   maintains the   display   blanked   until   the   magnetron has warmed up.  When the radar is turned on   by   pressing   the   WX/C   or   MAP   push buttons, it will display WAIT and will be in standby  for  the  1  minute  warmup  period, then  automatically  become  operational  in the selected mode. If   none   of   the   push -button    switches    is pressed,  the  radar  will  display  STBY  and be in the standby mode. 3.   Press   the   TEST    push    button    and, when  the  test  pattern  appears,  verify operation  of  the  intensity  control and adjust to desired viewing level. 4.   Observe  the  display;  verify  that  TEST is displayed in the Mode field and that the  test  pattern  exhibits  the  following characteristics: a.   Range   marks   and   alphanumerics are displayed in cyan b.   Color bar and 1  2  3 are displayed in auxiliary field c.   The  colors  of  the  first  three  target bands are green, yellow, and red WARNING