Mamiya C3 - sticky shutter button

Sigurd Veronetta · Jan 4, 2022

Greetings Fellow Weightlifters,

The shutter button on my C3 is a bit sticky or notchy, and has been since I first got it a while ago. By 'shutter button' I mean the sliding mechanism on the side which pushes down on the lens's own shutter lever.
After some fiddling and staring I noticed that the vertically-sliding part leans away from the side of the camera rather than running exactly perpendicular. The screw which hold it in place won't go in any further but leaves a gap of about 0.5mm.
If I push the button's mechanism against the body when I push down the button then the action is all smooth. Similarly if I use a cable release it's OK - the end of the release engages with a divet which pushes the mechanism against the body too.
It occurs to me that a washer might be missing but despite trawling through umpteen pictures of C3s I haven't seen anything to confirm or deny this.
So my questions are: am I missing a washer? Is something bent inside? Is this normal?
I've attached a couple of pictures which I hope show what I mean.

Thanks,

Sig.

Sirius Glass · Jan 4, 2022

We have many Mamiya C2xx and C3xx users here. One should jump in soon.

Welcome to APUG Photrio!!

gone · Jan 4, 2022

That vertical running bar is bent outward, you can see that clearly in the first pic. You could take it off and straighten it, but putting a washer in there like you mentioned should fix it too. Once it's off the camera you can go to the hardware store and find something.

Did you ck to see if the retainer screw has backed out?

MattKing · Jan 4, 2022

Welcome to Photrio.
I've never owned a C3, so can't help you directly.
But I do believe there are several other members here who do...

Sirius Glass · Jan 4, 2022

See that did not take long. Generally for the cost the service is good here.

grat · Jan 4, 2022

That screw with the two holes in it, should go in further. I'm looking at my C33, and there's no washer, but no gap, either.

If I had to make a guess (and I am), I'd say there's a problem with said screw-- either cross-threaded, or some crud in the socket.

grat · Jan 4, 2022

Similar pictures from mine:

Tel · Jan 4, 2022

grat said:
Similar pictures from mine:

View attachment 294777 View attachment 294778

Mine looks the same: the little brass screw fits snugly up against the release lever (without any washers). Try removing it and having a look in there--could be something fouling the mechanism and causing the release to bind. Playing with mine, I noticed that it's a bit sticky; I think I'll put a little graphite in there and see if it makes it smoother...

Sigurd Veronetta · Jan 5, 2022

Thank you for your responses and suggestions, the photos were helpful grat.

I had another look and the thread is clear - the whole of the threaded portion of the screw can go in. There were two very thin plastic washers, one under the head of the screw and the other between the sliding arm and the body. I think the problem is that the screw is not the right size because the unthreaded portion is too long - see the attached photo where I've propped it on the arm to check the thickness. (Yes, I've only just noticed the mucky splodge on my favourite pencil!).

Do the later C models have a thicker arm? If so perhaps that's where this screw comes from, or perhaps from a different kind of camera entirely. It looks like the solution is to get some more very thin plastic washers to build up the exact thickness necessary, plus apply some graphite to the sliding arm - any suggestions for what to look for when buying the latter?

Tel · Jan 5, 2022

Yes, that's definitely not the right screw for this application. Mine is brass with a slotted head (maybe an earlier version of the camera too). Somebody did a DIY fix and it didn't work. If I were in your situation, I'd use the washers, but put both of them on the outside of the release arm so that it rests flat against the body. After I'd lubricated it with some graphite of course. I get powdered graphite at my hardware store in a little squeeze-tube. But I've also found that a soft sketching pencil works and only puts the graphite where you want it. (The powder can be messy.)

Sirius Glass · Jan 5, 2022

If there is a hobby shop near you, you might find the right size screw. Otherwise you might want to contact www.KEH.com and ask the repair department if they will sell the correct screw to you.

Sigurd Veronetta · Jan 5, 2022

Tel said:
Yes, that's definitely not the right screw for this application. Mine is brass with a slotted head (maybe an earlier version of the camera too). Somebody did a DIY fix and it didn't work. If I were in your situation, I'd use the washers, but put both of them on the outside of the release arm so that it rests flat against the body. After I'd lubricated it with some graphite of course. I get powdered graphite at my hardware store in a little squeeze-tube. But I've also found that a soft sketching pencil works and only puts the graphite where you want it. (The powder can be messy.)

I've just looked through pages of images of C3s (and its descendents) and all have the same screw as mine, i.e. with two holes in the head. I think you must be the odd one out here!
So far as I can tell the moving arm is no thicker on other models so I can only surmise that the screw I have is a later replacement of the closest fit available to the repairer.
Looking at the C220 repair manual at butkus.org it has the order of assembly being screw - washer - arm - washer, which makes sense in terms of permitting movement.

As for the graphite, great idea - I'll dig around in my box of pencils.

Sigurd Veronetta · Jan 5, 2022

Sirius Glass said:
If there is a hobby shop near you, you might find the right size screw. Otherwise you might want to contact www.KEH.com and ask the repair department if they will sell the correct screw to you.

I'm not sure I can stand the stress of dealing with customs from the US to here on Crazy Island, but thanks for the suggestion anyway.

Mamiya_Repair · Jan 5, 2022

Sigurd Veronetta said:
I've just looked through pages of images of C3s (and its descendents) and all have the same screw as mine, i.e. with two holes in the head. I think you must be the odd one out here!
So far as I can tell the moving arm is no thicker on other models so I can only surmise that the screw I have is a later replacement of the closest fit available to the repairer.
Looking at the C220 repair manual at butkus.org it has the order of assembly being screw - washer - arm - washer, which makes sense in terms of permitting movement.

As for the graphite, great idea - I'll dig around in my box of pencils.

The correct part is a chrome plated pin face screw. There were slight differences in the shoulder length on the various versions of the C series. I can't tell from your photo, but the shoulder length on the attaching screw for the C3 should be around 2mm. Normally there is a plastic type washer between the screw and the arm then another washer between the arm and the body. But these screws are very thin (they were available in either 0.1-0.2mm) and should not be causing the lever to stick. I really would hold off on graphite-make sure that the arm and the body are clean and free from grease. Also, I often see the return spring broken on the arm.

Sigurd Veronetta · Jan 5, 2022

Mamiya_Repair said:
The correct part is a chrome plated pin face screw. There were slight differences in the shoulder length on the various versions of the C series. I can't tell from your photo, but the shoulder length on the attaching screw for the C3 should be around 2mm. Normally there is a plastic type washer between the screw and the arm then another washer between the arm and the body. But these screws are very thin (they were available in either 0.1-0.2mm) and should not be causing the lever to stick. I really would hold off on graphite-make sure that the arm and the body are clean and free from grease. Also, I often see the return spring broken on the arm.

Thank you for the information Bill. I've measured the screw and the shoulder is about 2mm long so my fix might therefore be as simple as it needing 0.2 mm washers rather than 0.1 mm ones. I shall ask some engineer chums for some.

Mamiya C3 - sticky shutter button

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