Collecting "freeze" data for 7D bodies running V2 firmware

Started Aug 12, 2012 | Discussions thread
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Larry Wallis
Regular MemberPosts: 130
Re: Larry: about contacts (battery ones & other)
In reply to jpr2, Sep 12, 2012

Ooops, amongst the hundreds of threads out there, I had forgotten about my postings here! Sorry not to have replied to your question jpr2.

jpr2 wrote:

did you ever experience intermittent malfunctions of cameras taken out of prolonged [supposedly safe, dry, smoke free, etc.] storage closets and shelves - which disappear after a bit of rubbing & cleaning?

My experience relates to all manner of electronic equipment, not specifically cameras. In short, all contacts can “play up” given the correct circumstances (or should that be “incorrect”!). You would not believe how much science and engineering is involved in getting reliable contacts in switches and plugs/sockets. As an extremely simple overview, in general, gold on gold is pretty good for low voltages and currents (like camera stuff), but silver is better for higher powers. Gold is better at resisting oxide build up than silver (other materials are also used, but gold is very common on higher quality low power stuff). Also, you need to supply sufficient current (known as the “wetting current”) to “cut through” any surface imperfections/oxidation. Sometimes, very low power circuits do not supply sufficient wetting current and this can eventually give rise to problems. Wiping contact surfaces over one another can be helpful as the wiping action helps remove any dirty layers.

So, if any item of electrical equipment is left in a “dodgy” atmosphere, it is quite possible that dirt/oxide layers can build up on contact surfaces and will lead to problems. It is hard to predict, but to state the obvious, a copper contact left for years in a dirty/salty environment will almost certainly fail; gold left for a few days in a clean atmosphere will almost certainly be fine. There is a sliding scale between the two extremes.

Again to state the obvious, do your best never to touch any contact surfaces with your fingers because your sweat can start to corrode the surface, and try to avoid getting dirt and grit onto the contacts (I think camera user manuals will say the same thing).

And, yes, as a general comment, I have come across many examples where equipment malfunctions have been caused by dodgy contacts, and which have been repaired following cleaning. IMO it is always worth trying to clean contacts if you are having an electrical problem, but of course, in something as complex as a camera, the only ones you can reach easily are on the lens and battery.

As a footnote, it is now known that Canon has fully recognised the “lock-up” issue as being due to the firmware. In this case, this does not surprise me. TBH the evidence was becoming pretty strong; to reiterate, my comments on contacts etc were primarily related to users getting error messages. In the early days of this problem, IMO, it was worth the usual re-install and clean contacts; however, once several people were reporting the same symptoms it became apparent to me that it was very likely to be the firmware interacting with some peculiarity of some cameras.

As has been mentioned elsewhere by others, I’ve also been surprised at the vitriol displayed by some contributors during their rubbishing of the idea it could be the firmware.

Larry Wallis

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