February 4th, 2010
Following the instructions here, I fixed my broken Nikon 55-200mm f/4-5.6G ED IF AF-S DX VR [Vibration Reduction] Zoom Nikkor Lens
First off, this is a great lens. I wish it would go down to f2.8, but, you can’t have everything for $200. Unfortunately, or perhaps by design, Nikon equipped this lens with plastic mounting lugs. Plastic can, well, shear off at the worst times.
I’ll post some pictures later, but for now, here is the fix.
Essentially, this repair consists of ordering the right part – the box is labeled B37, code JAA79851-B37. I called the Nikon parts department and just asked for the “mounting ring” for this lens.
Part in hand, you’ll need a tiny screwdriver.
Look at the base of the lens – you’ll see three parts. On the outside is the mounting ring we’re going to replace, there is a curved bit with contacts for the camera, and another part surrounding the glass.
Looking further, you’ll see three screws holding the surround part, two on the contact plate, and three on the mounting ring.
Remove the three screws for the surround part, then gently lift it off. Put the screws somewhere safe.
Now, remove the two screws for the contact plate. It’ll fall towards the middle of the lens, that’s fine. There is a thin conductor cable coming from it, just be easy and don’t force anything.
Take a deep breath, we’re about to do the hardest part.
Remove the three screws around the perimeter to free the broken mount. Gently lift up a bit and look underneath. Try not to disturb the shims under there, but I’m sure you will. Don’t sweat it too much.
Unlike the images in the linked article, my replacement part has an aperture loop (the long thing that sticks into the lens) instead of a plate. This loop is connected to the lens, and there didn’t seem to be an easy way to detach it. This loop is connected to the mounting plate with two very small screws, removed them, and I was able to lift the mount enough to look at the next challenge.
As noted in the linked article, there is a small wire leading to a contact on the edge of the mount. This contact consists of a screw, a bracket, a pin, and a spring. After that spring went flying off the table, I surmised it has a decent amount of compression. So, unlike me, carefully remove the screw and other parts from the damaged mount.
Half way done! Now, we just need to reverse the process.
I removed that contact pin from the new mount, and attached it to the wire coming from the lens. Carefully, put the mount back on the lens.
To attach the aperture loop, I used a toothpick to prop it up enough, then the magnetic screwdriver could take over. Two tiny screws later, we’re ready to reassemble.
First, we’ve got to deal with those shims. I used the toothpick to line the holes up, and indexed on the mount-screw hole just to the right of an indentation (where that contact pin bracket will wind up). Carefully, ease the connector plate back into position while putting the mount into position – harder to explain than it is to do, really.
Take another deep breath, the worst is over.
Replace the two screws in the connector plate.
Using that toothpick, I made sure the mount holes, shims, and screw holes were aligned, and replaced these 3 screws.
Drop the surround ring back into place, and replace it’s 3 screws.
Cross fingers, mount the lens on the camera. Mine worked the first time!