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



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SOURCE: The QRZ Windows Ham Radio CDROM