Lens stopped talking to body

btgc

btgc

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Jul 30, 2007
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Hello, how easy is to fry chip in early AF SLR lens? Yesterday unpacked it, mounted and it worked for some minutes - focused and body let set aperture from body (there is no aperture ring on lens). After some time I tried again and suddenly body isn't able to set aperture and focus anymore - it shows dashes as aperture and goes forth and back when trying to autofocus. Same happens also on second body. When mounted, aperture opens wide open so this doesn't look mechanical issue to me. Contacts are level and aligned like on other lenses, nothing wrong. I've cleaned contacts with a lens cleaning tissue.

I paid through PayPal but I'm amused by fact it worked when I mounted it for first time. I've used this system for years and never had any issues with it, lenses especially. Everything just works except this lens. And I don't feel I've anything wrong. Any ideas?

Do anyone can suggest what has happened? In-lens chip gone toast? Anything other?
 
You didn't say what lens and cameras. So mounting other lenses on the cameras still works fine -- the cameras weren't damaged?
 
I mentioned second body. One particular lens isn't working on both bodies, all other lenses are working on both bodies. Contacts have been cleaned once more, no luck.

Do fiberglass cleaner makes such a difference?
 
Had a similar problem with a Nikon F75 and an old 50AF. Sometimes it would work, other times it would cause the camera to go crazy.. that had me completely flabbergasted. Finally, I discovered the cause.. It was the way I used to mount the lens. A minute difference in the mount allowed the lens to be rotated a little further than the lens release catch if I kept the lens release button pushed in while mounting the lens. The result was that the lens's electronics were sometimes not correctly communicating with the body. I've since made it a habit to mount a lens without pressing the lens release and make sure that I hear the 'click' of the catch.. No problems since.
 
Just tried mounting the lens without pressing lens release catch, it turns until meets limiter and nothing.....Mounting with depressed catch it first shows two dashes -- where aperture should be and when lens mounts fully a point is added -.- probably showing there is a contact.

Mounting other lens it also goes through same cycles, dashes, dashes w/ point, dashes and then aperture shows up.

I removed tiny delimiter screw on lens mount and slowly mounted lens in hope it will engage a bit past normal position - nope. Aperture never shows up.

I would accept that if not first time when it worked. What has happened after first minutes of use?
 
Here is a picture of contacts (not my lens!)
http://www.pbase.com/pganzel/image/35488865

Is anyone familiar with this type of lens? I don't really understand role of spring there. There are five contacts and five wires in ribbon cable. One of contacts is a ground. Where from is fed and why spring is grounded?
 
Today I revisited lens and suddenly realized [semi]flexible ribbon cable soldered to contact plate has loose one or maybe two wires. Ribbon cable is rather stiff and looks like it is well connected but at some enlightenment I inspected back side of cable and noticed very tiny white streak across wire (inside brown plastic) which happily happened to be on one side so I could test it by carefully lifting ribbon from plate. Yes, it makes tiny gap but obviously that's enough.

My next move is to purchase conducting glue as my skills and toolkit are far from ability to fix this by soldering. Any leads on types or makes - I read there are crappy silver, good silver, graphite and copper based glues. Probably I need one which will fix well but not become brittle over time, well, nearest decade or longer if I'm lucky. I see on ebay many Chinese sellers are selling 0.2-0.3ml filled in syringe for a couple of dollars.

upd: I think I will continue in repair forum as issue isn't SLR specific - Repairing flat flexible cable.
new thread could be useful for other applications, too.
 
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