From INTERNET :

WIDER SSB BANDWITH ON THE ICOM IC-761 WITHOUT ANY
MODIFICATIONS
When in SSB mode and the filter switch is in the "out
position", your normal bandwidth is 2.6kHz.  When the filer
switch is in the "in position", your normal bandwidth is
2.4kHz.  I have noticed there is a 3rd SSB bandwidth for
receiving in the SSB mode.  Leave the filter switch in the
out position and place the IF shift button in the "in
position" for IF shift, and now the bandwidth is 3 to 3.2kHz
wide.  When using the filter switch only to select the
advertised wide and narrow position for SSB bandwidth, you
receive and transmit at those bandwidths and are using both
the 9MHz and 455MHz filters; however, when using the above
method as stated for the wider selectivity, it appears you
are receiving through the wide ceramic 455MHz filter only,
and bypassing the 9MHz filter.  So there are three positions,
not two.
       MODE       9MHZ           455           BANDWIDTH
       SSB        FL-80       CFJ-455K5          2.6
       SSB        FL-80       FJ-44A             2.4
       SSB        By Passed   CFJ-455K5          Approx 3.0

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IC-761 ACTIVATE TUNER WHEN IN GENERAL COVERAGE MODE

Remove  the  top cover of the IC-761 and locate  the tuner band switch unit
PC Board  which is the 2nd small PC board located  behind the antenna tuner
preset unit.   On the board, locate J 7 and at that location, you will note
a three (3) pin  molex plug with a black,  brown, and red wire connected to
it.   Either  unplug, remove, or clip the center brown wire coming from the
plug.   Carefully  unplugging the wire and placing  heat shrink tubing over
the end works very well.  This enables the tuner to be activated on GENERAL
as well as the ham bands.

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ALL BAND TX COVERAGE FOR ICOM IC761

 on the front marker unit

 cut r-37 and you have all band transmit