Canon 7 reglue shutter curtain?

[shawn]

When I went to advance my Canon 7 today the wind felt very odd. Opening it up and watching it while cranking it is looks the bottom leading edge of the curtain (second?) is coming loose from the metal bar and the curtain is starting to buckle in the track.

The curtain hasn't bent yet but obviously can't use it like this.

Any thoughts on repair? It looks like the body casing comes off pretty easily.

http://www.pentax-manuals.com/manuals/service/canon%207%20repair.pdf

Could it just be reglued or is something else going on.

Shawn

 

[retinax]

The body casing does come off easily, but I've not been in further than that, either. Iirc there's another repair manual on Pentaxmanuals that deals with repairing focal plane shutters. Re-glueing should be what's needed, some difficulty may lay in removing old glue and perhaps the black coating of the curtain.

 

[olliewtf]

The curtains themselves are stitched and glued to the metal rails. I would think its possibly your ribbon thats loosened - that should also be stitched around the bar, but only glued to the rollers.

If you're capable or confident enough to pull the shell, my recommendation would be (and i dont know the canon 7, but the mechanism is essentially the same on all focal plane shutters) loosen the curtain tensions (counting carefully how many turns on each) so the curtains are loose.

With the shell off and the curtains loose, you can easily inspect all the bits and hopefully find the issue.

If it is the ribbon has unglued from the drum, I would recommend regluing all the ribbons. use acetone to take them off and remove old glue, make sure you have marked where they go (their position is critical) and re glue.

As I said, no experience on the canon 7 but this really should apply to all focal plane cameras.


side note - inspect the curtains while youre there. if theres any cracks in the rubber, you may as well get used to the idea they need replacing.

 

[AndersG]

olliewtf, since the Canon 7 has steel curtains some parts of how they are connected to the rest may differ from the more common cloth curtains, possibly? Not that I know anything more than that the curtains are of steel in the Canon 7, though.

(And very much hope my Canon 7 stays working for a long time yet.)

 

[olliewtf]

ahhh thanks for that!

there must still be some kind of ribbon - the other option is that something is jamming the film gate, broken film perhaps.

Either way i think stripping the shell, and whatever comprises the inside of the gate to reveal / split the channels where the curtain ribbons run will reveal the issue.

but it depends how involved the OP wants to get.

 

[shawn]

Thanks, I haven't tackled this yet so these additional thoughts are helpful. I'd like to get it up and running so I will strip the shell soon.

Thanks,

Shawn