Repairing CPU contacts in a Nikon F90x?

[namke]

I have four lenses, (2 AF Nikons, 1 Tokina AI and 1 Vitacon AF). Of the AF lenses:

• my F4s recognises the two Nikon AF lenses, and the AF works correctly. The Vitacon lens is recognised as a 'CPU' lens, but the AF does not work.
• my F90x recognises the Vitacon AF lens, and the AF works correctly. However, neither of the Nikon lenses are consistently recognised as CPU lenses at all (the 50/1.8 is sometimes recognised, but more often - not). i.e. the camera deals with both as if they are simple AI lenses.

It's looking to me like there's something amiss with the F90x - possibly a dodgy CPU connection in the body - although the fact that one lens works is a puzzle to me.

Has anyone any experience of investigating such electronic repairs? It looks to me like the contact block is screw-mounted behind the lens mount. So it may be as simple as removing the lens mount, removing the block and taking a look.

Or perhaps not... I hate the sight of a small spring leaping for freedom

[P C Headland]

Have you tried just cleaning the contacts on both the lens(es) and bodies? Also try with brand new batteries.

[namke]

Batteries are brand new in the F90x, also I did try cleaning the F90x contacts (with DeOxit - which I use for audio connections). Cleaning contacts seemed to make a difference for a while, but the situation reverted in the morning (without dismounting the lens).

'tis a puzzle. I'm starting to regret my leap into modern technology (never had this problem with my Yashica FX-3 or FX-D !!)

[markbarendt]

The issue that I've had with my N90s's and CPU lenses is user error, a somewhat regular occurrence for me BTW.

If I get the aperture ring in the right place I'm good to go.

The problem is that most of the time I shoot in manual and I set the aperture with the lens. When I switch to speed mode the camera and I both get confused.

[namke]

Hmm. Could you expand on that?

I'm aware of the 'fEE' error - and this is not that When I attach the 50/1.8 AFD lens (for example), and turn the camera on, the LCD shows 'F--' and the matrix-metering indicator flashes. This is the same behaviour that I get when I attach an AI lens to the camera, so it looks to me as though the camera is not recognising the lens' CPU and treating it just like a manual lens.

Perhaps I need to be more rigourous, and lock the lens' aperture to f22 before mounting the lens..? I can't imagine why that would make a difference, but hey! I'll try anything if it works

[markbarendt]

Hmm. Could you expand on that?

I'm aware of the 'fEE' error - and this is not that When I attach the 50/1.8 AFD lens (for example), and turn the camera on, the LCD shows 'F--' and the matrix-metering indicator flashes. This is the same behaviour that I get when I attach an AI lens to the camera, so it looks to me as though the camera is not recognising the lens' CPU and treating it just like a manual lens.

Perhaps I need to be more rigourous, and lock the lens' aperture to f22 before mounting the lens..? I can't imagine why that would make a difference, but hey! I'll try anything if it works

I don't know the technical reasons, I only know that it is a requirement to use the auto modes other than "A".