Subject: TS-790A X-Band Repeat Mod

                  CROSS BAND REPEATER MOD
  To operate the TS790A in the repeater cross band mode,diode D32 on the
  control board must be opened.In addition,two resistors must be soldered
  to a 13 pin din plug which will be connected to the ACC. 2 jack on the
  back panel of the transceiver.

                  TO LOCATE AND OPEN D32
  1   Disconnect the power supply and antenna from the radio.

  2   Remove the 14 screws that secure the top and bottom covers.

  3   Carefully remove the top and bottom covers.

  4   Locate the control board. this is a vertically mounted board that is
      positioned approximately 1 inch behind the front panel.

  5   Locate diode d32 towards the top right side of the board.

  6   Using a small pair of wire cutters,cut the lead of the diode. do not
      pull on the lead or the diode as this may tear the foil on the other
      side of the board.

  7   assemble the radio by reversing steps 1-3.

             13 PIN DIN PLUG CONFIGURATION.

  1   Using a small flat blade screwdriver,lift up on the tab of the nylon
      cover.

  2   Once the tab clears the slot of the metal holder,pull the cover
      off the plug.

  3   Carefully separate the two metal holders and remove the pin assembly.

  4   First tin pins 1,8 and 11 of the assembly so the resistors can easily
      be soldered in place.

  5   SOLDER A 100K ohm,1/4 watt resistor between pins 1 and 11 of the
      assembly (the resistor leads should be cut and shaped before soldering).

  6   Solder a 1.5K ohm,1/4 watt resistor between pin 8 and the lead of the
      100K ohm resistor that is attached to pin 11.(the resistor leads
      should be cut and shaped before soldering)

  7   Wrap a small piece of electrical tape around the resistors.This will
      insulate them from the metal holder after the plug is assembled.

  8   Mount the pin assembly in the two metal holders.

  9   Slide the cover over the plug until the tab engages in the slot.
      The "U" shaped strain relief will not be used.

 10   Plug the 13 pin din plug in the ACC2 jack on the back panel of the
      radio.

                    OPERATING PROCEDURES

     The repeater cross band operation allows the TS790A to receive on one
     band and re-transmit the signal on the other band. Incoming signals
     will automatically be switched to the sub band.The TS790A will then
     re-transmit the signals from the main band. Each band may contain
     offset and sub-audible tone information (an optional TSU-5 must be
     installed in EACH BAND for decode).


  1   Press the MAIN function swich to select the MAIN band.

  2   Select the first operating frequency and mode (fm only).Select the
      offset as required.

  3   If the CH.Q is on,press the CH.Q switch to turn the function off.

  4   Select the sub-audible tone as required .

  5   Transfer the contents of the MAIN band to the SUB band.

  6   Select the second operating frequency anf mode (FM ONLY) and turn
      the CH.Q off.

  7   Select the offset and sub-audible tone as required.

  8   Adjust the MAIN and SUB band squelch controls to the threshold
      point.The TS790A will transmit in the repeater crossband mode if
      the squelch controls are set too low or a signal is received.

  9   Adjust the power control to allow normal output power from the MAIN
      band.

 10   Adjust the sub band volume control to a normal listening level to
      monitor incoming signals.

 11   To place the radio in the repeater cross-band mode,press the F.
      switch and then press the M.IN switch. An asterisk will light in the
      MAIN band display for confirmation.

 12   To cancel the operation,repeat step 11 and disconnect the DIN plug.

 13.  If the DIN plug is left in place after use,bleedover from the SUB
      band audio if present will be mixed with any transmitted audio.
      This will make your audio during a conversation hard to understand.

                   TSU-5 TONE UNIT

  When the TSU-5 tone units are not installed,only the tone (encode)
  function can be used.
  If CTCSS is to be used it must be installed in both bands to function
  with the cross-band repeater mode.

                   TX AUDIO ADJUSTMENT

  The audio gain can be adjusted by variable resistor VR36 on the IF unit.
  If the range of VR36 does not suffice for normal transmit audio,the
  values of the resistors on the 13 pin din plug can be changed.
  as an example,if the audio is too low,reduce the value of the 100K ohm
  resistor and increase the value of the 1.5K ohm resistor.

                 TO ACCESS VR36

  1 Remove the bottom cover of the radio to expose the IF unit.

  2 locate VR36

  3 Use a plastic alignment tool to adjust VR36 for normal TX audio.

  4 After the audio is adjusted,install the bottom cover.



   73 AND HAPPY MODING

   CARL

   packet: VE3ZCO@VE3GYQ BBS

   Internet: VE3ZCO@ardsley.business.uwo.ca
 
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