*MOD*TM-731A/E* KENWOOD *

Beep on/off:
Press call buttom and holding. Then 731 power off, and on.
Beep is off, beep on the same as told.

Freq:

Cut off the resistor r25 on the control unit X53-3250-XX frequency 136-174
400-500MHz. When also cut off r125 on the control unit and placed r124 then
is the TX in amateur bands.

Resistor dis. TX frq   RX freq    resetfreq   offsetfreq   stepfreq   IF
-----------------------------------------------------------------------------
r125 r124 r123 r25   o = used   x = not used
 o  o  o  o  m1  144-148  144-148     144        +-0.6        5   khz  10.7mc
 o  o  o  x  m2  136-174  136-174     144          0.6        5        10.7
 o  o  x  o  k6  144-148  136-174     144          0.6        5        16.9
 o  o  x  x  k3  136-174  136-174     144          0.6        5        16.9
 o  x  o  o  w1  144-146  144-146     144          0.6        12.5     10.7
 o  x  o  x  w2  136-174  136-174     144          0.6        12.5     10.7
 o  x  x  o  w3  144-146  144-146     144          0.6        12.5     10.7
 o  x  x  x  j3  136-174  136-174     145          0.6        20       10.7
 x  o  o  o  m3  136-174  136-174     144          0.6        5        10.7
 x  o  o  x  w4  144-146  136-174     144          0.6        12.5     10.7
 x  o  x  o  k1  144-148  136-174     144          0.6        5        16.9
 x  o  x  x  k2  142-152  136-174     144          0.6        5        16.9
 x  x  o  o  k4  144-148  136-174     144          0.6        5        16.9
 x  x  o  x  k5  142-152  136-174     144          0.6        5        16.9
 x  x  x  o  j1  144-146  144-146     145          0.6        20       10.7
 x  x  x  x  j2  144-146  136-174     145          0.6        20       10.7
-----------------------------------------------------------------------------
 o  o  o  o  m1  430-440  430-440     430          5                   30.825
 o  o  o  x  m2  400-500  400-500     430          5                   30.825
 o  o  x  o  k6  222-225  215-230     222          1.6                 30.825
 o  o  x  x  k3  400-500  400-500     440          5                   21.6
 o  x  o  o  w1  430-440  430-440     430          1.6 / 7.6           30.825
 o  x  o  x  w2  400-500  400-500     430          1.6 / 7.6           30.825
 o  x  x  o  w3  432-438  432-438     432          1.6                 30.825
 o  x  x  x  j3  400-470  400-470     433          5                   30.825
 x  o  o  o  m3  400-500  400-500     440          5                   30.825
 x  o  o  x  w4  430-440  400-500     430          1.6 / 7.6           30.825
 x  o  x  o  k1  438-450  438-450     440          5                   21.6
 x  o  x  x  k2  420-450  400-500     440          5                   21.6
 x  x  o  o  k4  220-225  215-230     220          1.6                 30.825
 x  x  o  x  k5  215-230  215-230     220          1.6                 30.825
 x  x  x  o  j1  430-440  430-440     433          5                   30.825
 x  x  x  x  j2  430-440  400-500     433          5                   30.825

Repeater operation:

Remove the r121 = 0 ohm from the control unit
           r122 = watchdog timer out

Press the F key, then press the ABC key within 5 seconds.
Each 3 dots light up on the frequency display indicating that the
repeater is on.
If signals are input to either band and the squelch is activated,
the signals are transmitted from the other band.

If the main band is 435MHz and the sub is 145MHz and signals are
input to the 145MHz band they are directly transmitted from the
435MHZ band.
If signals are input to the 435MHz band they are immediately
transmitted from the 145 MHz band.
In such a case however the mainband is 145MHz and subband is 435MHz.
When signals are transmitted for 3 minutes continuously operation
automatically changes into reception, by the action of the watchdog
timer r122.
Note: long term continuous transmission may cause foults

CTCSS on repeater side:
Set a desired tone freq, then activate the CTCSS
by this different tone freq can be selected for the output frequency

Mainband 439MHz tonefreq 88.5 ctcss on
Subband  145MHz tonefreq 67   ctcss on
The above setting makes it possible to use 439 repeater for 145 transceiver
67 tonefreq is added to 145MHz for access of the 731 allowing private use

This is a original for different country modification
By Kenwood Japan Corp.

      !                                        !
      !                    {}{}                !
      ==========================================
       !    o   !        o!x!      !   o   !
       !        !           /         !       !
     !=====================/====================!
     !                    r25                   !
     !!
      ------                         !!
        
               bottom side view
        
       front panel




     !                            o           : :
     !                                o        : :
     !o                           o   o    o  -----
     !o  o       o                    o       !   ! lithium bat
     !ooo  o       o   -----
     !o        r123   r124      !   r125    o  ::  r122
     !o                         ! o !!       ! : : ! 
     !o                         !!  !  o    !     !
     !                          !  !!
     ----    --------------------------------------------------
                                         r121

                control unit X53-3250-XX         foil side view

  = reristor (little smd jumpers)


--------------------------------


From: EA7FHR@EA7FKB.EAAL.ESP.EU
To  : MODS@WW

        TM-731 FREQUENCY AND CROSS BAND REPEATER MODIFICATION
        =====================================================
 
    The TM-731a will transcive between 136-174 MHz and 400-500 MHz as
    well as perform cross band repeter function when the following
    modifications are performed.
 
1.-  Remove both the  top and bottom cover. Disassemble the front
     	panel such that the control unit (X53-3250-XX) is accessable.
 
2.-  Remove R121, R123 and R25. While R125 snd R124 must be present.
 
3.-  If the time-out timer function is not desired, remouve R122 	as well.
 
4.-  Reassemble the unit and perform a microprocessor reset before
	operating the set.
 
5.-  Preserve your license by operating whithin the bands it is
	cover for.

EA7FHR @EA7FKB.EAAL.ESP.EU


-----------------------------------

Subject: TM-731A RPTR & OUT-OF-BAND MODS

Thanks to the efforts of our local technical wizard, Bob VE3GVD, we now have the secret to making the new Kenwood TM-731A do the same fancy tricks that its sister rig the TM-721A did.  Here is how it's done:

1) Remove the top and bottom covers, and take out the screws that will allow the front panel assembly to swing down.
2) With the rigs front facing you and the top side up, locate R 121 and R 125 which are both immediately to the left of the lithium battery.
3) Using a low wattage iron and tweezers, remove R 121 which is about the seven o'clock position with respect to the battery and reinstall it in the blank position designated for R 125 which is about the eight-thirty position with respect to the battery.
4) Now locate R 25 on the back of the circuit board that is attached vertically to the main chassis. (It's the board behind the front panel when the panel is folded up)  Carefully un-solder and lift off the grounded end.

That completes the mod.  Having a service manual, or at least a board layout will assist you in locating the components.  It will be neccessary to do a reset on the microprocessor as described in the user manual after doing the mods described.
For those curious as to what does what, removing R 121 enables the repeater cross-band function, and the adding of R 125/removal of R 25 enables the out-of-band features.

Weazle, VE3EAR @ VE3WZL.ON.CAN.NA
