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Ezio
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, July 21, 2004 - 03:41 am: | 
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I thought that thanks to this site I'd learned all I could possibly need to known about Canonet GIIIs with jammed shutters and fault advance, but I'm now facing a new puzzle. When this camera arrived, it was in the "classic" condition - blocked advanced lever, indicating that the shutter is cocked, and the shutter would not release. A standard shutter blade cleaning work, so I thought. However, upon opening and closing the back door the camera allowed the three advance strokes as it should, but then continues to advance and advance and advance while the shutter does not trip. I know that the free advance is a linkage problem, but what about the shutter? Do I have both problems simultaneously (fault linkage + jammed shutter), or is this a new twist? Is it perhaps possible that the shutter doesn't trip simply because it is not being cocked? Is there a way to check this? I would hate to go through all the procedure of cleaning the shutter blades, only to discover that they were not at fault. BTW: as a first step, I removed the front lens element to expose the shutter blades and gave them repeated lighter fluid showers, but there was absolutely no change. THANKS! |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, July 21, 2004 - 02:02 pm: |
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I don't think that both problems are related. The double release/double advance latch gets no feedback from the shutter (as on some other cameras like the Konica Auto-S2).
You can check whether the slider which is linked to the advance shaft moves after removing the bottom plate. When removing the front lens cell and some of the rings there should be a shaft approx. in the 7 o'clock position which should turn as you move the advance crank.
BTW did you check whether the self timer lever is in its normal position? Sometimes it happens that the self timer is jammed in the cocked position (there are some plastic cog wheels in the self timer gears), and the shutter won't fire when the self timer did not run. However in this case you should see a very minor movement of the shutter blades. |
Ezio
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 23, 2004 - 05:24 am: |
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The slider on the camera's bottom sems to move as it should (at least, it moves back and forth and I cannot imagine what other movement it could make), but there is another pointer at the shutter not being cocked - the small rear indicator window. When the back is opened/closed, the window turns white (as it should) and remains so for the first three strokes (as it should). Starting with the fourth stroke, however, the window shows red while the lever is being pushed (again, as it should), but as soon as the lever starts coming back it shifts to an intermediate position showing part red and part white. So, I assume I will have to try to figure out this as first thing. Of course, if the shutter is not being cocked then it is perfectly normal for the advance lever not being blocked - right? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, July 23, 2004 - 03:12 pm: |
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Not really, since there is no feedback from the shutter. The shutter release mechanism including the double exposure/double wind latch depends on pressing the shutter button only on the GIII.
The GIII has a lot of nifty features, but some of them may fail - I think in your case there are several failures which are not necessarily related to each other. |
Ezio
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, July 26, 2004 - 02:16 am: |
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I will go in some details because this is might be of use to others. The camera had two distinct and unrelated problems.
1) Shutter blades were jammed beyond any previous experience. Repeated washes with lighter fluid didn't even cause them to bulge a bit. However, pure alcohol did the trick. Alcohol + another subsequent light fluid shower removed what looked like a bungle of hair or more probably rests of a Q-tip. The shutter now fires pretty happily - but reads below.
2) The cinematic chain for shutter release is as follows. The shutter release button has two prongs. These press down a ring plate around the advance shaft. This plate has a front tongue, which is connected through an L-element to the vertical piece which trips the shutter. The L-element was neatly broken. I can't even imagine what amount of brute force must be applied to it to break it, but broken it is. Of course, with the camera top out I can fire the shutter by simply pressing down the vertical piece. The L-element is attached to the tongue of the ring plate with two screws, but the connection to the vertical piece is by two rivets so I doesn't look like it can be separated. So I'm pondering on whether weld the two pieces of the L-element back together (which would need to be done while they are still on the camera), or replace the whole vertical piece + riveted L element with the assembly from a donor camera that I have available. This doesn't seem an easy job, though, because there are a lot of connections and small screws and springs etc. that I would need to remove and reinstall. Anyone perhaps been there?
As regards the lack of double wind prevention, the jury is still out on this. With the camera in its present conditions, sometimes cocking the shutter would block the lever, and sometimes it wouldn't. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, July 26, 2004 - 04:08 am: |
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Thank you for your update. It clearly shows that sometimes malfunctions which occur at the same time are not necessarily related.
Replacing the shutter release mechanism of the GIII might be somewhat complicated, since the needle trap mechanism and auto aperture mechanism might be involved, too. Both are adjustable, but these adjustments are partially made by bending parts etc. The same applies for the over/underexposure shutter release latch.
So if you think you can make a solid weld of the l-shaped part, just do it.
BTW I once received a Konica Auto-S1.6 which was described as 'overwound'. And it was - the shutter was jammed, and these cameras have a feedback which does not allow moving the advance crank as long as the shutter has not fired correctly. Someone had turned the crank with brute force and misbent that double advance latch. If you ever had a look at this very solid mechanism on the early Konica rangefinders you can imagine how much power this must have taken. |
Ezio
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, July 27, 2004 - 12:08 am: |
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I'll try the welding this nest weekend. Incidentally, Winfried, although I will of course accept your statement to the effect that the GIII "normally" has no shutter feedback, this particular camera has a twist of its own. When the shutter is jammed, you can advance and advance and advance; if however the shutter is free and will fire, then the advance lever is blocked after the first stroke and remains so until the shutter is fired. The really funny thing is that the camera seems to know beforehand whether the shutter will fire or not. This is the first time I encounter a GIII with this behaviour. |
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