Fixing aperture blade mechanism

The lens is supposed to be locked at its smallest setting (largest f/number). You can control the aperture from the camera body, the same was as on a lens without an aperture ring. For example, in aperture priority mode (A), simply turn the command dial. In manual mode (M), hold down the exposure compensation button while turning the command dial.

That was for a lens with the electronics to communicate with the camera. If you have a purely mechanical lens, you must shoot in manual mode and control the aperture by turning the ring on the lens. There should be a small orange slide near the aperture ring, Slide it toward the front of the lens to unlock the ring.

If you need more help, please feel free to reply to this post. Please specify the lens when you do.

The FEE error indicates that the camera cannot control the full range of the lens aperture. If your lens has a mechanical aperture ring, rotate the aperture to its smallest opening, or highest f-number - normally marked in orange. Select this aperture and lock it using the aperture locking switch to prevent this message from appearing again.

These lenses are highly complicated, and require adjustment after reassembly. Even if you do get it fixed, you do not have the necessary adjustment software to get it working properly. Try sending it to PhotoTech Repair Service in NYC. They are Nikon authorized, and factory trained with all the necessary equipment. Also if you join they're facebook page, they will give you a 10% discount.
Here is the facebook page link, it has everything you need to send it in.
http://www.facebook.com/pages/New-York-NY/PhotoTech-Repair-Service-Inc/102527215194

your efforts are appreciated,must be careful,since disturbing optics result in poor/bad formation of image,if optic surfaces,convex, concave,etcchanges u willnot get image formation as aperture unit is in between the optics,step by step carefully disassemble take out the apartur unit, set the diapharm blades and then assemble.

Yes. A good camera technician can partially disassemble the lens and then thoroughly clean the blades and the rest of the aperture diaphragm mechanism. This is commonly referred to as an internal CLA (cleaning, lubrication, and adjustment). This is a very nice macro lens and it is worth repairing if it otherwise is in exceptionally nice condition.

You probably have oils on the aperture blades and they do not close to the F stop you set as quickly as required, thus causing the over exposure. Easy to pinpoint: sent the aperture to full open (F1.8) and use appropriate shutter speeds as determined by the camera (in manual mode), if the picture does not over expose, then the problem is with the oiled contaminated aperture blades. Have it cleaned.

It does sound like your lens diaphragm/aperture ring coupling mechanism is in need of repair.

From your description, Yes. All RB67 lenses have common problems, usually sticky blades. Since there are 2 sets of blades, (shutter and aperture), the shutter blades may be contaminated with oil/debris

You are able to shoot at F8 by opening the lens barrier and sliding the macro switch to the Macro mode. This provides a mechanical aperture of F8. We recommend the use of this setting either when shooting close up images or when shooting images in a very brightly lit scene. Unfortunately, because the aperture is mechanical, the EXIF information is not recorded. Therefore, you can not see whether you photographed an image in the Macro mode or if the aperture has been changed. However, you can physically see the aperture close down by looking at the lens with a magnifying glass or loupe when turning the sliding the macro switch to the Macro mode.

You are able to shoot at F8 by opening the lens barrier and sliding the macro switch to the Macro mode. This provides a mechanical aperture of F8. We recommend the use of this setting either when shooting close up images or when shooting images in a very brightly lit scene. Unfortunately, because the aperture is mechanical, the EXIF information is not recorded. Therefore, you can not see whether you photographed an image in the Macro mode or if the aperture has been changed. However, you can physically see the aperture close down by looking at the lens with a magnifying glass or loupe when turning the sliding the macro switch to the Macro mode.