Model:         IC-765                          Revised 11-10-89

 Division:      Amateur

 Note:          This service bulletin is meant for technical per-
                sonnel with experience working on solid state com-
                munications equipment.  Damage caused by im-
                properly installing this modification may cause
                ICOM to charge for subsequent repairs to the
                product.  ICOM does not warrant this modification.


 Bulletin #:    26989R1

 Date:          September 26, 1989

 Subject:       The antenna tuner on some IC-765s "hunts" during
                transmit after the first tuning phase is complete.
                This may start after a few months of use.

 Information:   The feedback circuit that controls the tuning
                motors may become sensitive after a few months of
                use.

 Procedure

  1.  Remove the top cover and locate the antenna tuner board.

  2.  Locate R5 and R10 and set them to the center of their range.

  3.  Set the following controls on the radio as indicated below:

              Tuner - On
              Frequency - 7.1 MHz
              Mode - LSB

  4.  Transmit for 10 seconds.

  5.   Verify V-ref at R4 is between 4.6 and 5.3 VDC.

  6.   Adjust R5 for a voltage that is one half of what was
      measured in step 5 +/- 0.1 VDC measured at R2.

  7.   Adjust R10 for a voltage that is one half of what was
      measured in step 5 +\- 0.1 VDC measured at R7.

  8.   Verify proper tuner operation on all bands.

  9.   Reinstall the covers and return the radio to operation.