Canon P Shutter Curtain Adjustment

farlymac

farlymac

PF McFarland
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I want to try adjusting the tension on my second curtain to see if that will cure the travel coming up short, and leaving a gap to overexpose the film.

After taking the bottom off (then doing searches on all usual places), I'm not sure which way to turn the adjuster to tighten it. From what I can see, it's a matter of loosening the screw in the center of the shaft, release the catch pawl, then turn the adjuster clock-wise. But then it could be the other way, so if you've done this operation before, please advise me on which direction to go.

Thanks in advance.

PF
 
I broke a Canon 7 doing this very item. The screw in the middle is not strong, it split in half. You should be able to tell which way is tighter or looser by the design of the pawls?
 
Ranchu said:
I broke a Canon 7 doing this very item. The screw in the middle is not strong, it split in half. You should be able to tell which way is tighter or looser by the design of the pawls?
Click to expand...

I went in and started on the one I thought would get the curtain to close the gap, but didn't have much luck with it. Then I started to adjust on the other one, and the gap started to disappear.

After several adjustments, the gap finally closed, but when I ran through the speeds, it was capping at 1/125 and above. So some more adjusting cured that, but now it's gapping again. But it's very inconsistent, with different gap widths, and sometimes no gap.

With the camera all closed up, and the lens mounted, it sounds a lot better than before with a nice ssshick most of the time. But every once in a while I'll get a shiiirk, which to me sounds like it needs lubrication.

Not sure how far I have to disassemble it to get to the lubrication points for the curtains, but from the drawings it appears to be pretty much down to the shutter crate. Like the Yashica YF, I'm thinking it's better to send this one to the experts.

PF
 
Two things I've figured out on the camera. One; the odd sound that comes every once in a while is the run-on of the drum when the second curtain gaps. Two; it's working okay at up to 1/250 speed, no gap, no cap. So I'm going to load it with some T-Max 100 tomorrow, and check out the lenses (2.8/50 and 1.8/50 Canons, 4/90 Leica Elmar).

PF
 
If you have incorrect curtain speeds, it is more likely due to increasing drag in the system than a change in spring tension. If you try to correct it by increasing spring tension without first correcting the cause of the problem, you will probably find that the travel speed is still not uniform, and you may overtension the springs or cause other damage. Make sure the bearings are clean and properly lubricated before adjusting the springs, and also make sure there is no dirt or foreign matter in any gears that are meshed to the curtain spindles. Obstructions like this will cause the curtains to hesitate regardless of the amount of spring tension.
 
The speeds sound good, Rick, with one second being real close. It's only gapping now at 1/500, and 1/1000. I mainly made two half turn adjustments to start, and when they didn't do anything, I backed them off, and went the other direction. As I went along, I started shortening the turns to avoid any problems. Still, no one has told me which way is tight or loose, or which way to go for capping or gapping.

PF
 
Just had a look in the (combined) service manual of the Canon VI-T, VI-L and P.

Not much help there, only exploded views and part lists. No explaining alas !
 
hanskerensky said:
Just had a look in the (combined) service manual of the Canon VI-T, VI-L and P.

Not much help there, only exploded views and part lists. No explaining alas !
Click to expand...

Yes, Hans, that was my experience also. I was about to buy a copy off eBay, when I came across a post with a link to the pentaxmanuals site. Funny thing is I bookmarked it a long time ago, and forgot they had the Canon stuff too. The manual for the 7 has a lot of things in it, but when it comes to adjusting the shutter, it assumes you already know how to do that. How I miss Classic Camera Repair.

PF
 
hanskerensky said:
Results look good Phil !
So you managed to get the shutter adjusted :)
Click to expand...

Thanks, Hans, but I was only partially successful. I can't use 1/500 or 1/1000, and the temperature affects the operation, which is a lubrication matter. I'll have to send it in for a rehab, as I'm leery of tackling a full tear down myself.

PF
 
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