It appears that you may have made an error in the modification. I modified
an IC-751 where I had to cut a wire, and it didn't do it. I later
discovered I had cut the wrong wire. Made the change and all is well.

The IC-751 is not as sophisticated a unit as yours; the CW filter gets
selected by a front panel pushbutton. Perhaps there is an 'enabling' step,
such as cut a diode or something. Reread the instructions on installation
from ICOM.

If nothing seems to work, I would be pleased to help you with it; trouble
is, I'm in Los Angeles.

73, Bob K6DDX