Fixing my EFS 17-55

27 Dec 2025 · Part 1 · Still Broken · Clumsy

At least the original fault is fixed

I've got a Canon EFS 17-55 lens. Its got a faulty aperture flex cable. It's a common problem on this lens. I like a project over Christmas, so I ordered myself a couple of flex cables (I either end up with a spare or I use them both!) and watched a couple of stripping your EFS 17-55 videos. The one I found most useful is from Cameras Lens Etc. If you have a faulty flex cable. This guy's videos are excellent.

I stripped the lens down on Boxing day, all was well until I came upon a teeny tiny screw that was well coated in epoxy, by well coated I mean under a blob of it. I scraped it off as best I could then proceeded to round out the screw head. Darn I said to myself, this has added a little spice into the mix. I tried various tricks, piece of rubber band, cutting a slot, filing a slot, everything made it worse. So i wrapped the area in blue tape and set forth with a 1mm drill bit.

My tool of choice for careful drilling is my Bosch GSB 120. It's a compact drill driver combo, smaller and lighter than my other blue cordless tools, but still packs a punch. Thankfully the screws are made of cheese, so couple of minutes very carefully drilling and pop, the head spun right off.

The rest of the stripdown went without issue. 15 minutes (or so) later I had a fully stripped lens and a nice tidy screw layout.

The aperture is controlled by an open layout motor, the flex cable attaches to the coils, when I desoldered the old flex cable I noticed that the third connection to the coil was bad. The tiny (way smaller than a hair) wire was not connected to the terminal of the flex cable. I assume this was my cack handed desoldering and not the root cause of the problem I was having. I attached the wire back to the contact and then attached the new flex cable to the aperture unit.

I tested it as best I could, electricity was flowing, continuity was continuous, happy days. Now get it all back together. I took some time to clean the lens elements, the sliders and in fact everything inside the lens.

Getting the lens assembly back together is a bit of a faff! I'm glad I marked the tubes to make reassembly easier (that's a very relative term!). When the main assembly is back together the next step is to reattach the USM body. As I was making sure the focus ring was working I was clumsy and dragged the metal USM body over the stabaliser flex cable and twisted it... Which broke it. Oh shoot I said to myself.

Stabaliser flex cable — Stabaliser Flex Cable, Broken.

Not ideal, but recoverable. I'll just get back onto my favourite purveyor of electronics bits and order a new one. Sure it's a faff, but it'll be here in a week or so and it'll be back snapping an hour later. I'm on the second day of searching and so far all I'm drawing is blanks. I've messaged a few sellers I've used in the past, one has said no, one has said no but I sell the complete stabaliser (with a flex cable attached) the third hasn't replied yet.

Right now I have a lens in 12 pieces where the original problem is fixed (I'm assuming it's fixed, I've not been able to test it yet!) but with a newly created problem, that isn't as easy to fix. I've got a friend who has the same lens that's broken looking for it, I'll keep my eye out on ebay for a spares/repairs one, and I'll keep scouring the land of the rising sun.

So it's 2/3 assembled, all the screws are labelled and in a plastic screw holding tub, the feelers are out and I'm in a holding pattern. Hopefully the third seller will come back to me and it'll be sorted? Maybe my friend comes through and gives me his broken lens? Maybe I end up with a paper weight and a life lesson about taking care with flex cables when test fitting stuff? Either way, I'll update this post when something happens!