[Icom] Strange IC-765 40 meter problem

[Joe Stepansky]

For brief background, I began noticing something interesting with my 
IC-765's performance on 40 meters earlier this year.  The receive level 
would occasionally reduce considerably and suddenly (i.e. one second the 
band sounds normal, the next it's severely attenuated).  After hitting the 
keyer, even briefly, everything returned to normal.  I noticed this 
happened more in windy conditions than not, so assumed it was my 40 meter 
beam.  Also noticed that sometimes the SWR would go up to 3:1, then back to 
a more normal 1.4:1.

Decided to replace the balun and coax on the beam.  Also checked everything 
else out while we were up there.  All looked fine.  Came back down, fired 
things up, had a 1.2:1 SWR.  Stations sounded fine.  Then the receive 
problem kicked in again, and the SWR is now > 3:1!!

Is it possible this is something with the 765??  Has anyone seen or heard 
of this happening?  It's so bad that even the antenna tuner won't knock the 
SWR down.  I don't have another rig to test it with, so now I'm 
stumped.  But we've replaced virtually everything that can be replaced on 
the 40 meter beam, so I'm now out of ideas.

Any suggestions will be more than welcome.

73, Joe KQ3F