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Andrew_s
Tinkerer
Username: Andrew_s
Post Number: 1
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 24, 2008 - 08:11 pm: | 
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Hello everyone! I just recently purchased a 1981 Canon A-1 slr camera and have run into an interesting issue. I shot a roll of film and only three frames showed up when developed, the rest of the film is blank, nothing. When I test the camera with no film in it and the back open I can clearly see the shutter open and close and everything appears to be working normally. The camera was recently serviced (lube and light seals) so that doesn't seem to be an issue. Any insight to the problem would be a huge help. Thanks! |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 608
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 25, 2008 - 04:48 am: |
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The first question that comes to mind is film transport: did the roll of film travel to the end until you could not wind any more?
Second is the electromagnet that releases the second curtain: if this fails to hold, the shutter could run closed. You would still see it operate, but you would not see light coming through it as you watch it fire. Check your speeds with the TV test to see that they are all in the ballpark.... |
Andrew_s
Tinkerer
Username: Andrew_s
Post Number: 2
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 25, 2008 - 12:32 pm: |
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Even though the battery check light looked ok, I went ahead and replaced the battery to see if that made a difference. Before replacing the battery I noticed that on 1/60 shutter speed, the shutter wouldn't always fire consistently...sometimes I could see though it and sometimes not. Everything below 1/60 seems to fire accordingly and I'm not sure that I can see anything 1/125 and above with my eyes, I know the curtain moves because I see it draw back across the opening when I move the advance lever but I can't tell if it's opening correctly. Oh, and yes the film travels normally from one side to the other. |
Mndean
Tinkerer
Username: Mndean
Post Number: 54
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 25, 2008 - 07:34 pm: |
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I second the recommendation of the TV test, providing you have an older pre-digital television. It's easy and very informative. See the details on Rick's site at this address:
http://rick_oleson.tripod.com/index-135.html |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 609
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 26, 2008 - 04:14 am: |
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It sounds like a magnet problem .... it may just need cleaning. |
Scanogram
Tinkerer
Username: Scanogram
Post Number: 10
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 26, 2008 - 08:07 am: |
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There really is only 2 choices here, the magnet is not holding or the first curtain is running too slow. I would think that you would have problems on the slower speeds if it were the magnet. How does it work on the bulb setting? If it works ok, then the magnet is probably ok. If the first curtain is running too slow, the second curtain will catch up to it. This will affect the higher speeds. At the bottom of the camera you will see two geared wheels, the one at the rear of the camera is the first curtain. You can add tension by turning the wheel one or two clicks at a time (I use a pointed dental tool to turn them). If the shutter needs lube this may not help. It's major disassembly to properly oil the curtain rollers. |
Andrew_s
Tinkerer
Username: Andrew_s
Post Number: 3
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 26, 2008 - 10:10 am: |
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Thanks for the link to the tv test! I've taken the bottom plate off once, how would I go about cleaning the magnets? Ok, I tried the test and when the camera is set to 1/125 the opening looks more like the 1/500 or even the 1/1000 speed illustration. Also, it often takes 5 or 6 fires in order to be able to see an opening at all when the shutter fires. Again, only present on the faster speeds for some reason. Scanogram, I take it that the bulb setting is the 1/60? At that speed I can see though it and sometimes not, it's pretty noticable when I can so it's a big difference. The rest of the time it looks like the higher speeds, I can see the shutter travel, but no light come though. Thanks for everyone's help so far! I think we're getting close. |
Msiegel
Tinkerer
Username: Msiegel
Post Number: 27
Registered: 03-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, June 26, 2008 - 10:50 am: |
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Hi,
bulb setting is "B" the setting that holds the shutter open as long as the release button is pressed. Has nothing to do with flash bulbs.
1/60 should be marked X (or printed red) and marks the flash synch speed.
Martin |
Scanogram
Tinkerer
Username: Scanogram
Post Number: 11
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, June 30, 2008 - 03:26 pm: |
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Andrew sorry I'm so slow, it took me a while to find my manual. The picture shows the closing curtain electro magnet (top center). Carefully clean the surfaces of the armature and magnet core where they press together. Fire the shutter a few times and you will see where they come together. I use some tissue wrapped around the tip of some tweezers with a small amount of alcohol. The picture is from an AE1 but I believe the shutters are identical.
[IMG]http://i81.photobucket.com/albums/j228/scanogram/can6n.jpg[/IMG] |
