Weird Canonet G-III QL17 aperture problem

[ItsReallyDarren]

I just got a G-III QL17 from ebay. Everything seemed to checkout alright. The body is fairly clean, no major dents or dings. The leatherette is kind of dry and the light seals are gone, naturally. Checked for any any stuck shutter and aperture blade problems, shutter no, noticed something weird with the aperture blades though. The viewfinder is pretty clear but Im still gonna clean out the glass. Dropped a mercury battery in and the light meter seems to work. The shutters seemed to fire at the right speeds, through when I select a slower speed such as 15, 8, or 4 it makes a slight buzzing noise on the ring, ditto when the shutter depresses (im assuming the buzzing/ticking after the shutter button is normal).

The only weird part I noticed was with the aperture blades. When I cocked the shutter the aperture blades would stop down to what was selected. After firing a couple of shots I noticed the two aperture blades located to the bottom left would move very slightly back to the original would-be placement after the shutter was tripped.

I drew a quick diagram to show the movement of the blades.

Im not sure if I should just leave it be, send it back, or have it CLA'd.
(I paid about 60 bucks for it off ebay)

1: Before shutter fires

2: After shutter fires

 

[1948nikon]

Overhaul Shutter and Aperture Blades

Overhaul Shutter and Aperture Blades

The Canon is in need of complete shutter and aperture overhaul. Because of the simple design of this particular model it is not beyond the layman and a few simple tools and some secret ingredients. ( NO Never Any Oil)

 

[former member]

> The only weird part I noticed was with the aperture blades. When I cocked the shutter the aperture blades would stop down to what was selected.

When the camera is set on manual, the aperture will remain at the setting that was used when the shutter was fired. When uncocked, you change the f-stop setting, and the blades stay mothionless UNTIL you cock the shutter. That is the camera's Trap-Needle mechanism working properly. On automatic t is essetially using the force of your finger to stop down the aperture blades until they hit the stop indicated by the moving needle. You can learn to push the shutter release in carefully and use as an exposure lock. On Manual- it is using the force of the shutter mechanism being cocked.

The slow-speeds use a clock-work mechanism, and you are feeling the timer running. When you select the speeds, you feel the clockwork mechanism being "wound".

I ran through this with a camera in hand, good battery, no film.

I've flood-cleaned at least 15 Canonet's on the kitchen table. Also repaired some electrical shorts. Replaced a lot of light seals. Replace the seals and put some film through it.

 

[ItsReallyDarren]

Ive shot a video highlighting the problem. One at f/16 and one at f/5.6 to illustrate the problem.

http://s10.photobucket.com/albums/a143/ItsReallyDarren/?action=view&current=P1030762.flv

http://s10.photobucket.com/albums/a143/ItsReallyDarren/?action=view&current=P1030761.flv


1948nikon,

Have any good places to look for repair information?
The only place I know of now if kyphoto.com