PCS4000
                             HEADQUARTERS
                           NEW JERSEY WING
          United States Air Force Auxiliary, Civil Air Patrol
                    P.O. Box 16099, Building 34-34
               McGuire Air Force Base, New Jersey  08641
               (609)  723-8200           (609)  723-8205


Reply to                                                  15 May 1984
Attn of:  DCE/DCL

Subject:  Azden PCS-4000 Busy /Scan Mode Modification

     The following  is from LTC  Albert Beutler  (ZIGZAG 19).  He has
developed  a modification  that will  convert the  scan mode  to what
he calls  a more  conventional arrangement.  His  modification  is as
follows:
          "The Busy/Scan  mode of  the  Azden PCS-4000  scans until a
     signal  is  received, pauses  for  about five  seconds, and then
     resumes  scanning unless you are quick  enough to hit one of the
     keypad  buttons to stop  the scanning.  It is then  necessary to
     manually  restart the scanning.  This modification  converts the
     Busy Scan Mode to the more conventional arrangement in which the
     radio scans  until a signal is received, stops  scanning as long
     as the  signal is present, and then  resumes scanning about five
     seconds after loss of signal.  
     The five second scan resume delay
     is sufficient to  prevent scanning restart  on momentary  signal
     fades and no signal periods between  transmissions of  different
     stations in  a net or  in  a  roundtable.  The  modification  is
     fairly simple, requiring  the installation  of a single diode on
     the receiver board.

          "Place the  set upside  down on  the bench  and remove  the
     bottom cover.  Remove the  cover slowly  so as  not to  yank the
     speaker wires loose  from the PC  Board.  Locate IC303  near the
     front of the receiver  board.  It can  be seen at the lower left
     of the photo  on page 14 of the Azden  PCS-4000 Manual, with the
     arrow running  from (A), running  across it.  Pins 3,4, and 5 of
     IC303 are tied together on the PC Board.  Connect the Anode of a
     1N914 or 1N4148 diode  to one of  these pins.  Pins 9  and 10 of
     IC303 are tied  together on  the PC Board.  Connect the  cathode
     end of the diode  to one of these  two pins.  Take care to  make
     the solder connections  as rapidly as  possible to  minimize the
     amount of heat conducted from the pins into the IC.

          "Replace the bottom  cover and enjoy."  That's all there is
      to the modification.  Have fun with your new modification.