The diode to remove is first diode to top left of lcd, when looking at main board upright with lcd display facing you, and case is opened.

Removal of castle nut on antenna connector,all case screws including two small screws above and below mic jacks is required to open case.

I have done this mod and have had good results.

I have tested all functions of the radio after the mod including upload and download from computer with excellent results.

Regards
Davo

This has been added to the article 08-04-2006.

The BNC Antenna ferrule is held on with some kind of super glue in the threads so you will need to work this nut loose ever so carefully.
Just a piece of information that you may find useful, the antenna ferrule rotates clockwise to tighten, and counterclockwise to loosen.
Use a jewelers (or small type) screwdriver ,a small hammer ,and a pair of needle nose pliers.
Place the tip of the jewelers (or small type) screwdriver ,into one of the notches of the BNC ferrule and tap the handle end of the screwdriver with a small hammer ever so lightly until it begins to move.
Once it gets moving put the tips of your needle nose into the ferrule notches ,and rotate it off. This requires time ,so take as much of it as you need.
Re-assembly is the reverse of above procedure.

The other possibility is to visit your local Icom radio shop or repair depot.
They may be able to remove the nut for you safely for a small or no charge?
I would do the latter ,if you feel this is too awkward.
Once both counterclockwise rotation notch edges of the ferrule get rounded, the procedure becomes much more difficult for removal (even with the correct tool) ,and a new nut, and or BNC connector ,and the possibility of repair exhists.
Worst case scenario, a new plastic radio body/case may be required for ?$?

They tell me the icom factory tool to do this is quite expensive.