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Message |
    
Fred pageot
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 01:54 pm: | 
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Hello, on lasts b&w pictures taken by my FTB, I have a dark stripe on the right of the picture about 1mm large. Does anyone knows what could be the problem ? I changed the light seal 6 months ago. Thanks |
Jim Murray
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 02:20 pm: |
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My FTb did the same thing. The second shutter
curtain rod is catching up to the first. Have it
CLA'ed and make sure the tech is aware of the
problem. |
fred pageot
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 03:05 pm: |
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sorry for not understanding but what CLA'ed stands for ? |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 03:38 pm: |
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Fred,
It stands for cleaned,lubricated and adjusted.
Glenn. |
Richard Creviston
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, September 14, 2005 - 07:02 pm: |
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Fred; Jim is probably correct. This seems to be a common problem with FTB's. To confirm that this is the problem try the following:
This problem can be detected by removing the lens and with the back of the camera open and shutter speed set at highest speed, point the camera toward a diffused light source. Fire the shutter while observing
the shutter opening from the rear of camera. You should see a complete frame of light if the shutter is not capping. Anything less than a complete frame indicates a problem. Practice this a few times and you will see what I mean. If the observed frame is dark on the left side it would indicate a too slow condition of the first curtain. (Or too fast second curtain which is not likely)
This problem occurs due to the 2nd shutter curtain overtaking the 1st curtain before the 1st has completed it's travel. It usually is an indication of the need to lubricate the curtain shafts which turn in a brass bushing.
I have corrected this condition on two of my FTB's. If you are inclined to correct it yourself please Email me for details. Richard.
[email protected] |
Richard Creviston
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 15, 2005 - 03:14 pm: |
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I have received several Emails regarding this subject so will post answers pertinant to it. Apologies for long but necessary message.
This problem can be detected by removing the lens and with the back of the camera open and shutter speed set at highest speed, point the camera toward a diffused light source. Fire the shutter while observing
the shutter opening from the rear of camera. You should see a complete frame of light if the shutter is not capping. Anything less than a complete frame indicates a problem. Practice this a few times and you will see what I mean. If the observed frame is dark on the left side it would indicate a too slow condition of the first curtain. (Or too fast second curtain which is not likely)
This problem occurs due to the 2nd shutter curtain overtaking the 1st curtain before the 1st has completed it's travel. It usually is an indication of the need to lubricate the curtain shafts which turn in a brass bushing.
If there is a squeaking sound it would suggest the need for lubrication which requires major disassembly. However in my case (No Squeaking)
I corrected the problem as follows.
Remove the bottom plate. Note the two small gears on the rewind side which are secured by two pawls. The front gear (Nearest to lens) controls the second shutter curtain. Rear gear controls the first curtain.
The pawls which lock the small gears is secured by a Left Hand Screw.
This screw is usually cemented which will require you to use a small brush and acetone to dissolve the cement. Do not rush this this cement removal and use the acetone sparingly until all traces of cement are removed.
The screw, being a left hand screw, will now be removed by turning it
Clockwise to remove it. This screw is very fragile and will snap easily if all cement has not been removed.
Disengage the pawls from the gear teeth. Don't be concerned about the gears turning when you release the pawls as they will remain in position.
In order to adjust the gears I modified a small common screw driver by cutting a square notch in the blade to fit over the gear so as to turn it.
Turn the Rear gear Counter Clockwise to increase tension. (Gears are easier to access if you cock the shutter first.) Start with about 1/2 turn and check for capping. Repeat as necessary until capping disappears.
Don't be dismayed if you snap the tiny screw which secures the pawls as this happened to me the first time I tried this. There is no tendency for the adjusted gears to move without the pawls in place. However I used a tiny drop of clear fingernail polish to secure the gears in case there may be a tendency for them to move from their newly adjusted position.
Of course this procedure is a quick fix and may not work if the curtain shafts are badly in need of lubricating. And of course the shutter speed may be slightly altered. I have used this method on two Canons with successful results.
Hope this helps you. Please advise if you have further questions about this procedure. Let me know how it turns out.
Sincerely, Richard Creviston.
[email protected] |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 15, 2005 - 06:15 pm: |
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The above stated fix is probably why capping is now a common problem on FTb cameras.One should never advocate increasing blind tension, without first ensuring that the internals have been cleaned and lubricated properly.
Lack of lubrication is not the only cause of shutter capping on the FTb.The nasty habit of storing a 30+ year old camera with the shutter cocked, will also cause this problem.
When the shutter is set up correctly,the first curtain spring tension is always greater than the second.Thus when stored tensioned for long periods,the first curtain spring is the one that always takes on a greater 'set'.This leaves the first curtain spring with less tension to move the curtain.Just increasing first spring tension will only compound the problem by increasing the probability that this spring will take on further 'set'.Quite recently I repaired a FTb in which the only fault,besides lack of lubricant,was the fact that the first curtain roller had become spring bound because of quick fixes.
In 1973 I purchased two FTb to supplement our laboratory's F1 kit.The FTb were used in the field by general staff members.One was lost in a test rig explosion,the other I purchased when the laboratory went digital.Being built like the proverbial brick s**thouse the camera works today as well as it did in 1973.New light-seals and lubrication are all it has ever needed.
One last thing,have everything clean and lubricated properly and you will soon find out why the Canon engineers bothered to spend the extra money on pawls to lock the tensioned rollers. |
TimW
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 22, 2005 - 02:47 pm: |
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Are the curtain shafts easy to get at and lube on the Canon FT I wish to attempt this before looking further on a capping problem.
thanks Tim. |
Fred pageot
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 17, 2005 - 12:03 pm: |
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Hello just to give a feed back on this problem : I am not skilled enough to apply the procedure given by Richard yhen I decided to open bottom of the ftb and to blow dry air (computer dry air cleaner)on the mechanism and on the belts slowly. I tried the procedure to diagnose the capping curtains, and nothing is happening : frame is clear and full. I had the light seal rebuilt by a specialist 3 mùonths ago and the old one was in really bad shape falling in piece, evrywhere in the camera, and I hink this was the cause of the problem. Nevertheless thanks for your time and answers.
Fred. |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 17, 2005 - 04:14 pm: |
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Are you now saying that the FTb is working and you have the negatives to prove same?Also from what you have said in your posts here, the light seals have been changed twice - once by you six months ago and then again by a specialist three months ago,is this correct?
If you find the problem has not been solved by blowing out the foam particles/dirt,have the camera properly cleaned and lubricated.As I said; fiddling about with curtain roller tension, on a camera that is clearly in need of a clean and lube is not the best way of solving the problem long term. |
Fred Pageot
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 20, 2005 - 12:26 pm: |
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Hello Glenn,
I tested on one negative pushed to 1600 ISO to have the higher shutter speed and yes the negatives are for the moment quite good. In fact I just have the light seal changed by a specialist not by myself. And now after a blowing everything seems to be working. But how you suggested I will make it CLA as soon as possible.
Thanks for all your help, this is an excellent forum.
Fred |
Glenn Middleton
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 20, 2005 - 03:05 pm: |
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Fred,
Glad all is OK.My query about the light seals was because Canon FT and A series leak light at the hinge rather badly when the end seal goes.On the FTb fitted with the QL device the end seal can be a bit difficult to replace properly.I was just wondering if problem was a light leak and not shutter related,but without seeing negs I could not say.
Normally the degrading foam particles are small enough not to jam a FTb shutter.However if a larger piece had become dislodged during replacement,this could have caused your problem.
Glenn. |
