Fixing a stuck Canon lens

(last time I had problems with this glass was when lens protector did its job)

I've been using my Canon EF-S 17-85mm lens (with image stabilizer) as my primary general purpose lens for a long time now. It wasn't cheap (if I recall correctly, around 800eur) but it has served me well. If you want to look for drawbacks, it is a bit large and heavy, but its usefulness as "good enough for almost any situation" (yet not perfect for any, really) glass overweighs that my far.

Lately zoom started "sticking". First it could be persuaded to loosen with some wiggling of zoom but lately it grew bad enough to be practically permanently at one position. Time to see what could be done. And apparently my google-fu was strong enough as first link was to video for fixing this very issue.

So, to work.

And all the photos that have this lens pictured are taken with Canon's 50mm EF lens. Really cheap (around 100 eur when I bought it years ago) but damn is it great - that is the lens I to use for most of the product shots I take. Still, photos taken here are taken with camera held in hands and with relatively bad lighting so blurriness and general lack of focus can be expected.

Flat flex cables, flat flex cables everywhere! You'll need to be extremely careful with those, as breaking them accidentally is very easy and repairing them is just about impossible.

That said, I have to marvel the system design of these lenses. All the electronics is on this single board, connected to motors and so on via those flex cables. One might wonder why they chose to use total of 4 different types flex connectors here (one at upper right opened by pulling small tabs on sides of flex out; two below it by opening "lever" type holder and rest are friction-locked; you'll just push the flex cable in it.

My guess would be that many of these flexes and connectors date back to earlier models; when some features were later added (like stabilization) they just added new type flex and suitable (cheapest?) connector for it, using older flexes/connectors for older features.

Other side of said board. Since there are inductors on board I'd guess there's switching regulator (or multiple regulators) on board, but none of the chips I looked are easily found on net, most being Canon's ASICs (except H-bridge motor driver, for focusing motor I guess) . No surprises there, really, and I wasn't feeling too adventurous so I returned to repair quite soon.

After some disassembly the culprit was reached. Three screws around the inner body had come loose, preventing normal operation of zoom mechanism. Tighten them and all works properly again. And then add some suitable glue (like loctite) to make sure they don't get loose again.

Note the small hair just above upside "85", lower and left from the indicated screw. When you got two dogs their hair is everywhere even when the dogs themselves aren't around. I had to remove several hairs from the lens body during the process, and I expect some are still in there - inner structures aren't sealed (even when lens is fully assembled, although it is relatively closed package then) so dust and hairs can get in way too easily. Not to mention this kind of projects.

First quick test photo after assembly. Everything still works, excellent! Some pars were yet to be replaced as you can see.

And all that remains now is to replace the protector glass. So about two hours of work saved me the cost of a new lens. Time well spent.