Mamiya C330 distance scale shutter - a horror tale

[eumenius]

Hello friends,
My flu is still very bad, so I had a chance to see what I can do about the inoperative distance scale shutter on my Mamiya C330f. It’s easy to remove a side cover, so when I took it apart I saw a puzzling combination of levers, all misplaced perhaps by a previous repairman. The aluminium shutter was firmly kept in place by a piece of wooden matchstick. I had to figure out how the whole system works, and that wasn’t too easy – as I have expected, the scene was missing something important. The scale shutter unit seems to be of exceptionally bad mechanical design – I even thought that some guys from Krasnogorsk or Arsenal should have sneaked in Mamiya constructors’ office and changed something in their blueprints The shutter is spring-closed, there is an another long lever on the cover, also spring-loaded, that transfers a movement from an another lever that senses a small chromed screw on the rack. This latter lever should theoretically have a small steel pole on it, against which an adjustable screw of lever 2 presses. This adjustment screw is needed to adjust an infinity position, and can be found under a small black plastic cover. The problem with my camera was simple – thanks to ingenious design, the pole was broken off the lever, so it became disconnected. I didn’t find it inside the camera, maybe it was thrown away. I tried to make it from good copper wire, but with no success – the load on it is so high that it was bent off from its place after 10-15 focusing movements back and forth. I think the only way to cure it is to make a steel pole again, but with no warranty that it won’t be broken soon like an original one. I did find some information about numerous problems with distance scale among C330 users. Maybe the main source of troubles is a weak pole that breaks off the lever? Judging from the lever shoulder ratios and springs employed, it SHOULD break sooner or later. I will try to fix it from the pure interest, but I seriously doubt that I would ever use the distance scale. So my advice is: if your C330 does not open a shutter on a scale, weep not – it seems to be a serious headache to fix, and not much gain. Interesting enough, how many other fragile poles have been put in C330 by its constructors, eh? Fortunately in left side compartment of C330 is no big gears whose tooth could be damaged by a broken piece of steel.

Cheers,
Zhenya

 

[dr bob]

No problem with mine in 40 years. Eyes a little weak now so the scale is not often used.

 

[Lee Shively]

I honestly cannot ever remember using the distance scale on either of the C330's I've owned.

I consider the distance scale on these cameras to be like the bright line frame lines in Leicas--a nice approximation but not really accurate enough to depend on.

 

[eumenius]

No problem with mine in 40 years. Eyes a little weak now so the scale is not often used.

That's great, but maybe they used another materials those days? My C330f is obviously younger than 40 Or your specimen is a very lucky one? The camera seems to be built to last a lifetime, but this unit is really badly designed

 

[dr bob]

That's great, but maybe they used another materials those days? My C330f is obviously younger than 40 Or your specimen is a very lucky one? The camera seems to be built to last a lifetime, but this unit is really badly designed

O.K. I'm busted! Maybe more like 38 years, not 40, but who's counting at this age? There have been other issues, but again who's listning?

 

[grahamp]

The window in the body is only needed for the 80mm and below. The other lenses read against the front edge of the body.

The scales used in the earlier versions of the C series were better. At least they had no moving parts!

 

[Donald Qualls]

Zhenya, you might try replacing the broken pin with music wire. It should be available in a variety of sizes from model building suppliers (used for lots of stuff in model airplanes and similar), and as it is cold-drawn carbon steel, it is very hard and stiff and extremely strong for its size. I used it to repair (replace, really) the firing pin in a pistol some fifteen years ago; still have the pistol, and the repaired firing pin is still fine (and it takes a lot more stress than anything inside a camera).

Don't try to cut the stuff with cutting pliers, though; you'll notch the jaws. Instead, either notch it with a file or grinding stone and snap it over a hard edge (like cutting glass rod or tube), or cut it with an abrasive cutter like a cutoff wheel in a rotary tool. It can be soft soldered (electronic or plumbing solder) without detempering, if the work is done carefully to avoid applying more heat than absolutely necessary to melt the solder. I think you'll find it more than adquate for the part you describe...