Fixing an Old Film Camera, Part 2: First, Do No Harm

Close-up of Olympus OM-2n dial

“First, do no harm.” That’s a credo that should be applied to all repair attempts. It’s easy to break stuff while you fix something else, especially when you don’t know your way around. I learned this the hard way fixing up an old film camera, but I ultimately came through a winner. Let me explain.

In part one of this series, we tracked down and price out an old, broken manual film camera for repair. Today we’ll see how I fixed up an Olympus OM-2n. Spoiler alert: once diagnosed, the repair was dead easy, a simple loose screw blocking the entire film-winder and shutter mechanism. But along the way, I did do harm. Lots of harm. But fixing it was a learning experience.

The Olympus OM-2n I picked up was manufactured from 1979 to 1984, and as we shall see today, almost entirely mechanical. Once researched and armed with the correct tools for the job, it was time for step one: diagnosis.

Diagnosing the problem

This is usually the hardest part, especially if you have no experience of fixing a particular item. In this case, the problems were a stuck film winding lever, and a stuck shutter release. There was a little, promising amount of play in the lever, but the shutter button wouldn’t move at all.

I started off with Google, and found a few common problems related to the symptoms. None of these proved to be the actual problem, but I did find a  video that proved essential when reassembling the bottom section of the camera. It’s also an extremely soothing video to watch any time:

Most of the shutter and film-winding mechanisms are in the bottom of the camera. Taking off the bottom plate is easy: remove four cross-head screws (use JIS screwdrivers, because Phillips screwdrivers can strip the heads), secure the plate, and then lift it off to reveal this:

Arrow pointing out the location of a winding gear on the bottom of an Olympus OM-2n

I won’t go through everything I tried, but the gist is that the film winding lever is connected to pretty much everything under here, via cogs and levers. When you stroke the lever, it turns the indicated cog via a shaft that comes from the top of the camera. This in turn winds the film, cocks the shutter-release, and—I assume, because I didn’t get that deep—cocks the mirror flip-up mechanism (What could go wrong? – Ed.)

The indicated cog would wiggle when I waggled the film-wind lever, but something was binding the motion. Slowly, over several days, I disassembled any section that was driven by this cog, and any other that seemed to be stuck. Meanwhile, I put screws and cogs into a little plastic box with small sections, or stuck them to masking tape. I also took a ton of photos. In fact, I wish I had taken more, because you never know which tiny, hair-like spring you’ll need to reseat until it pings out of the camera and disappears under the desk. 

Unfortunately, I missed the loose screw that was causing the problem, and moved on to checking the top of the camera. This is a little trickier to remove. First, you have to take off the top of the film-advance lever. I used a rubber-covered plate off an old iPhone stand, which gave me enough grip to turn it. Then, you lift off the lever, rescue a washer, and use a pin-wrench (or some tweezers, in my case) to unscrew the retaining ring. 

Top half of Olympus OM-2n with cover removed

Next, you remove the flash shoe, and the retainer under that, and finally, you remove the rewind crank handle. This whole process is outlined in this post on the Olympus OM-1. In fact, many parts are shared between the OM-1, OM-2, OM-3, and OM-4, so guides for one can often apply to another. Or at least give you hints.

In the end, opening up the top caused more harm than good. I was able to clean out some perished foam that had turned to gunk around the pentaprism, but I also broke the on/off dial, and had to keep removing and replacing the lid to recalibrate the film counter, align the ISO/exposure compensation dial, and fix that broken on/off switch (details on that one below). You should really think, research, and second-guess whether you need to dive into sections that may have nothing to do with your broken bit.

Mode selection dial of Olympus OM-2n
This counter sits atop the film-advance assembly. It has a spring which needs to be tensioned enough to return it to zero.

In this case, though, opening the top did let me remove the entire film-advance assembly (it lifts out after removing a few screws), and to inch closer to my final diagnosis. And like this whole repair operation, it taught me a ton about how cameras work, and how amazingly engineered they are, like oversized wristwatches.

The solution!

My final clue was the rewind release knob:

Olympus OM-2n front, with rewind release button pointed out
The rewind knob finally gave away the camera’s secret. 

When you twist this knob, it turns a cam, which disengages the film winder. It does this by lifting a shaft that runs through to the bottom section, so the cog on the bottom no longer engages the rest of the winding and cocking mechanisms. It connects to the gear indicated in the first image of this post. After removing that long lever covering it, all I had to do was tighten the screw. It turns out that a loose screw on the bottom end of this shaft was stopping the gear from turning. Problem solved. The lever winds, the shutter cocks and fires, everything that was broken now works as it should. Now all I had to do was put everything back together. 

Like any repair, reassembly is just putting things back in, reversing the order of disassembly. But unlike something like a Mac —where a few leftover screws is no problem—with a mechanism like this it all has to be perfect. In the end, I got it all back together, but when the camera still wouldn’t switch on, I realized that I’d broken the power/mode switch along the way.

The power switch

Take a look at this:

Camera mode toggle on Olympus OM-2n, after disassembly by author
The OM-2n power switch. Missing bits drawn in by author.

That’s the broken power switch. If you don’t line up this switch with the corresponding external switch, then you can break it when you replace the cover with any kind of snap-in-place force. Which I did. Twice. I’ve drawn on the outline of the switch as it should be. The fork formed by that brown section, made from PCB material, moves pins attached to its underside to different copper traces, connecting different circuits. This switch is used to select manual, auto, off, and battery-test positions. It’s essential, so I had to repair it. 

Adding a chunk of leftover wood to fill in the broken mode selection toggle
Sizing up.

For this, I reused an old plywood shim from a previous guitar repair. I cut new tips for the fork, and superglued them, edge-on. To strengthen the joint, I added two more strips on the back of these new prongs. Thin, fluid superglue, patience, and tweezers saved the day.

Broken mode selection toggle from Olympus OM-2n, with wooden fill-in piece
Partially fixed.

This little hack saved the day. I forgot to take a picture of it before replacing the lid, and now that it all works, I’m not opening it up again. It works fine, though.

A new camera for $35

Now that I’ve fixed up one camera, I’m ready for another, especially now that I have a bit of experience. I may tackle a different brand, but it’s tempting to stick with Olympus, so I can use my new knowledge. 

So, what’s next? Well, there’s one more job before putting in the first film. Well, two jobs—I also need a lens. But before that, the seals that keep light from reaching the film inside need to be replaced. This is very common in older cameras. The foam used to seal the light around the rear door perishes, and flakes off in bits. It’s easy to buy new foam. Japan Hobby Tool sells it in several thicknesses. In Europe, you can order from Micro-Tools in Germany

In the third and final part of this series, we’ll explore  how to fit new light seals, replace the mirror damper, and test that everything works. See you then.