DIY Sekor C Lens Repair?

[PentaxGuy87]

Hello all,

I recently picked up a Mamiya 1000s. It my first medium format, and I'm really excited.

Anyway one of the two lenses that came with it doesn't function properly. The 80mm 2.8 aperture blades do not move. They are stuck wide open. As I have a working 45mm, and the 80 is so cheap i'd like to try repairing this myself.

Does anybody have any good info on lens repair, MF Sekor or otherwise? Figure it's worth a shot to do it myself.

Thanks & keep shooting!

 

[Jon Shiu]

I don't know anything about repairing them, but have you checked the A/M switch?

Jon

 

[PentaxGuy87]

Yes i checked the A/M switch. It's not that. I read that the oil used on the blades get stuck after a time. So hopefully its just a matter of lubing them.I just don't want to rip apart this lens without some frame of reference.

 

[Jon Shiu]

As to lubing the aperture blades- there is not supposed to be any oil on them, so clean them, but no lube.

Jon

 

[CGW]

Also possible the linkage for stopping the aperture down--and not the blades--is the problem. Jam or a busted spring?

Do some searching on your own but start here:

http://photo.net/medium-format-photography-forum/00YN3k

 

[Rudolf Karachun]

I repair Sekor shutters for my C330 TLR before. You shall disassemble the lens from the shutter, open the shutter cover plate and remove the shutter speed adjusting ring. I don't remember all detail, but as I remember the all other parts stay in place after removing the cover and don't need to be touched at all. Only the shutter speed adjusting ring will come of together with the shutter front cover. When the shutter open, put it in the Lighter fluid for a some time. Let it soak and move the aperture from time to time until it not start moving free as it supposed to be. This is it. Remove shutter from the lighter fluid, let it dry and assemble it back. You don't need to grease something, all internal parts shall be oil free. You may only put a little grease on the shutter speed adjusting ring itself, and the back of the shutter cover plate. Be careful when installing back the shutter adjusting ring. The little pin witch travels inside of the figured opening in the shutter adjusting ring are very thin and sensitive and it brakes easily, don't force it in any way and try not to touch the top tiny part witch is traveling inside the figured opening. If it is necessary to move that pin during the shutter back assembly touch it for the bottomed part witch is more bigger in diameter then the top. That pin is made from a very soft metal and I personally break two shutters by moving pin inappropriately. When assembling the shutter don't tight the nut to much, because the frictions between the Shutter speed adjusting ring and the front cover will prevent shutter speed ring from moving. I didn't recommend to do any other dis-assembly of that shutter at home. I disassembled one of this broken shutters by my self, and it fail apart after removing just a few screws and I never was able to put them back in order.

 

[CGW]

Don't think the OP has a Mamiya TLR.