Stored Sigma 105 EX Macro Stopped Autofocusing

This lens was bought new in 2000 and used occasionally for a couple years, then sadly it sat in a camera bag with its caps on for a few years untouched. Last time I used it it worked fine but when I tried using it again on my new 7D it doesn't autofocus. It's doing the same thing on my old SLR as well. It just whirs and whirs if it's way out of focus but if I move so that it's closer to focus it chirps and chirps like a whispering chipmunk. Manual focus, of course, still works. Could it be something simple like cleaning the connections? Simple for someone who knows how to do that I guess, I never have so I don't know. I'm short on cash for a bit so I'd rather try the simple things I can, maybe, do before taking it to a shop where I could get charged a pile for a simple cleaning.

Any thoughts? Any other info I can provide that would help you help me?

Quick, sell it on eBay. Send it to Sigma for an estimate. Have you considered using it MF only? Most macro work is done that way.

Yeah, I do of course use the macro part of it mostly in manual but I also liked using it as a close up but not quite macro lens where the AF was handy. Unfortunately Sigma, as far as I know, does not have a Canadian service office, they go through a place called Gentec... sounds shady to me.

Are you sure the clutch isn't disengaged?

Do you mean the slider ring from AF to M? If so, yup.

I was using this lens for some manual focus manual work and the following error showed up on the screen: "Communication between the lens and camera is faulty. Clean the lens contacts."

Okay. How?

I just googled that phrase and the only search result was this thread.

Have you tried it on another camera??

Try cleaning off the contacts between the lens and the camera body with a pencil eraser and see if that clears it up.

yogestee wrote in post #9182669
Have you tried it on another camera??

The only other body I have is an old Elan II, what I upgraded from to my 7D So, I don't get any errors with it but the lens behaves the same way that I detailed in the first post.

I tried the eraser thing, nothing changed.

The lens was taken to Gentec for service, $107 later...

Repaired diaphram base plate
Replaced main PCB
Upgraded firmware
Adjusted and cleaned

So far, not very far admittedly cause I haven't had much of a chance to test it, it's worked very well.

I love the bokeh on this lens, it's nice to have it back.

Do you have a DG or non-DG out of curiousity?

My non-DG sadly didnt like my 7D and had to go back..

Come to think of it..i still havnt gotten my money back from that and they received it well over a week ago..

Non DG, It was bought in 2000, pre-DG days, thus the firmware upgrade/main PCB upgrade.

ions wrote in post #9134451
Sigma, as far as I know, does not have a Canadian service office, they go through a place called Gentec... sounds shady to me.

Not shady at all - Gentec are the Canadian distributor for Sigma, and are great to deal with.

Uhh yeah, I know now. See 3 posts up.