TM 55-1510-220-10 CAUTION Prior  to  insertion  of  an  impulse  cartridge, be  sure  there  is  preformed  packing  in  the flare     cartridge.          (There     will     be     no preformed   packing   in   chaff   cartridges.) Reinstall   any   preformed   packing   that   is inadvertently  removed  with  dustcap.    The loading of impulse cartridges into a flare or chaff shall be accomplished one at a time. 5. Insert one impulse cartridge into each flare (or chaff). 6. Install retainer plate assembly by screwing to two retainer bolts into payload module. WARNING The system must have been tested to assure that   there   is   no   stray   voltage   and   all aircraft  power  must  be  removed  from  the system    prior    to    unloading    the    payload module. 7. On the dispenser control panel, assure ARM-SAFE switch is in SAFE position. 8. On the electronic module and right wing assure safety pins and flag assemblies are installed. 9. Slide payload module assembly into dispenser assembly and secure two stud bolts,  hand tight, using 5/32 inch hexagonal wrench. b. Ammunition Unloading Procedure. WARNING All  aircraft  power  to  the  dispenser  system must   be   turned   off   prior   to   removal   of payload  module  from  dispenser  assembly. Safety   pin   flag   shall   be   installed   in   the electronic module prior to landing and the safety   pin   flag   shall   be   installed   in   the wing-mounted   safety   switch   immediately after landing. 1. On dispenser control panel, assure ARM- SAFE switch is in SAFE position. 2. Assure safety pin and flag are inserted into electronic module and in the wing mounted safety switch. WARNING If   there   is   an   indication   that   a   misfire occurred, notify emergency ordinance disposal    personnel    for    disposition    and disposal. 3. Remove module from dispenser assembly by unscrewing two stud bolts with a 5/32 inch hexagonal wrench and sliding out of dispenser assembly. 4. Remove retaining plate from payload module by unscrewing two retaining bolts. 5. Remove expended and unexpended impulse cartridges and flares (or chaff) from payload module. 6. Repack unexpended items in original containers and return to stores. NOTE It  is  not  unusual  for  the  case  of  a  chaff cartridge to crack when fired.  It does not effect  performance  of  the  item  and  should not be reported as a malfunction. 4-6. RADAR SIGNAL DETECTING SET (AN/APR39(V)1). The  radar  signal  detecting  set  (fig.    4-3)  indicates  the relative  position  of  search  radar  stations.    Audio  warning signals are applied to the pilot's and copilot's headsets.  The radar   signal   detecting   set   is   protected   by   the   7.5-ampere circuit  breaker  placarded  APR  39,  located  on  the  mission control panel (fig. 4-1).   The associated antennas are shown in   figure   2-1.      For   operating   instructions,   refer   to   TM 115841-283-20.  Self test pattern shall be as shown in figure 4-5. a. Radar Signal Detecting Set Control Panel Functions (AN/APR-39(V)1). (1) PWR switch.  Turns set on or off. (2) SELF TEST switch.  Initiates self test. Change 2      4-9