I was able to fix my 35mm with these instructions - THANKS FOR POSTING THEM. I didnt have a stuck focus ring, mine did move with some resistance, but the front lens wouldnt move in or out and the distance indicator wouldnt budge either.
Some recommendations:
1.) Do read everything posted here thoroughly. Try to locate everything mentioned. It really helps. The explosion diagram found elsewhere is of some use, too; print it out or have it on screen.
Then, go buy better screwdrivers. If you have really good ones already, go fetch a metal file. I ruined a set of cheap ones, than bought really good expensive ones and still had them go blunt every 5 or so screws. that's what you need the file for. some screws are incredibly tight, but that's ok, the lens is surprisingly sturdy. apply the necessary force, you dont have any other option anyway (unless you own some kind of specialty power tool for this purpose, a big one with a diesel engine.)
2.) Disassembly: The bottom part of the lens consists of three distinct parts: the silvery metal bayonet, a black plasticky part surrounding the back lens element and another plastic part that carries the contacts. the latter two are separate, even though it doesnt look that way.
First, remove the three 120 degree separated screws that connect the shiny metal part to the lens body. then, take a close look at the black plasticky part; it can be removed without tools. then, remove all the screws that connect the contacts to the shiny metal ring. that's not strictly necessary, but it makes things lots easier. If you arent a real expert at this sort of thing, you should do this.
3.) next, remove the screw that connects the circuit board to the lens body. now, here's where i made a mistake: there are three cable-like thingies running down from the circuit board into the lens. two are pretty sturdy large ones, but the third is a small 3 lane one. this one is super fragile and rips very very easily. i didnt know this and severed it. since you'll need a lot (and i mean A LOT) of force to unscrew the problematic bracket, you'll most likely want to desolder this one, else you'll likely rip it (unless you're really expert with this sort of thing); after desoldering, you can flip the circuit board upwards and get full access to the bracket. the soldering/desoldering is super simple. heat up the solder with a soldering iron, dont pump it away or anything, but move the contacts from the cable-thingy out of the solder blobs with your soldering iron. put something in between the solder points (i.e. some tape or a bit of paper) to avoid turining them into one big blob of solder. once you're finished, re-heat the first solder point, dip the contact thingy into it, wait till it gets hard. way easier than doing the full desoldering limbo. just make sure that you dont get any contact between the individual contacts.
4.) loosen the bracket as described. DO HAVE YOUR LENS SWITCHED TO AF WHEN YOU DO THIS.
5.) if your lens was in MF mode, your AF/MF switch may be stuck. look underneath the circuit board right behind the switch. there should be some sort of shiny silvery rod thingy sticking up. push on it with a screwdriver. also try pushing and prodding everything else (gently.) it should make "click" and the button should move freely again.
6.) since you didnt desolder and are a bit clumsy with tools and delicate electronics, your AF doesnt work. that's because you severed the cable-thingy mentioned above. your chances of reconnecting the severed lanes are basically nil, unless you're used to soldering under a microscope. here's what i did (and what worked): First, desolder the cable, suck up most (not all) of the solder (if you dont know how to do this, google for desoldering, there's a lot of good howtos for this. a desolder pump thingy is
4 euros, spend them if you dont own one already. dont try without one (or a suitable replacement, such as solder wick.) flip up the circuit board; you'll find that the cable thingy runs down to three nice big protruding metal contacts. solder a thin wire to each of them. solder the other ends to the contacts on the circuit board. burn yourself several times (if you're clumsy enough to sever the cable, you'll sure as hell burn yourself.)
7.) check if the aperture still closes when you change the f-value and push the aperture preview button on the camera. if it doesnt, check the other cables. you probably ripped one of them. it's unlikely that you wrecked the circuit board, else i'd have wrecked mine too. i'm that clumsy.
8.) dont even try opening the lens from the front. it's easy, but completely pointless. there isn't anything you could reach that could be broken in there.
9.) if you dont tighten the bracket as brutally as it was when you found it, you might find that your manual focus is way more smooth and the AF runs a tiny little bit faster. dont leave it loose though, fasten it as good as you can (if you're still reading this, you're not the type of person that can get the screw as tight as canon did anyway.)
If anyone finds out about a decent hood for this lens (for crop dslrs), please post about it here. The one from canon is a fat disgraceful cornflakes bowl.
Cheers,
Geocidal
