What would you do? Minolta Hi-Matic G shutter problem

[xkaes]

The Hi-Matic G is a great little auto-exposure camera, but this one has a problem.

The camera has a two-blade diaphragm & shutter combination. That's right just two blades act as the aperture and the shutter in combination.

Depending on the ISO and the light, at f2.8 the shutter speed is 1/30 and as things get brighter the combination changes gradually to f14 at 1/650s. A needle in the viewfinder points to the combination that will be used -- but the needle can be locked by pressing the shutter release slightly, offering some manual exposure control.

The shutter/aperture works great at 1/650 all the was down the 1/125, but when the speed drops to 1/60, the shutter opens fine, but closes very slowly.

The two blades are clean as a whistle, so there is something else that is gooped up.

The top and the bottom plates would be easy to take off, but the shutter/aperture is in the back of the lens -- all of the glass (4/3) is in front of the shutter/aperture.

How would you approach this problem -- other than buying another Hi-Matic G?

 

[benderscameracorner]

I've not had to take apart my G yet so can't help with internal woes, but just confirming the obvious first: are you using a fresh battery and is it a Wein Cell, hearing aid battery, or something 1.5V instead of 1.35V?

 

[xkaes]

Yes, it's the correct battery and the needle responds correctly to light. I'll also add that when I switch over to "FLASH" mode (1/30s), no matter what GN (f-stop) is selected, the shutter/apertures opens correctly but is very slow to close -- just as in Auto-exposure mode.

I'm not going to spend much time with it, I've got a very nice G2, and expect delivery of a GF in a couple of days. The GF has three, manually set aperture settings (f4, f8, f16) that are Waterhouse stops, and two manually set shutter speeds (1/30 & 1/125), so what could go wrong?

 

[monopix]

I would fix it. Have fixed them in the past but they're not easy to work on.

 

[Dan Daniel]

The shutter/aperture works great at 1/650 all the was down the 1/125, but when the speed drops to 1/60, the shutter opens fine, but closes very slowly.

The two blades are clean as a whistle, so there is something else that is gooped up.

I don't know this camera or shutter, but based on the image posted by monopix, it looks like a typical mechanical slow speed escapement is part of the shutter. Based on what you say is happening, I'd expect that the escapement is gummed up or such, causing the very slow release.

 

[xkaes]

That photo from monopix is from a Hi-Matic F which is completely different animal from the Hi-Matic G. The Hi-Matic F, and some other earlier Hi-Matics, used an electronic shutter based on the famous Yashica ELECTRO shutter -- with the "ATOMIC" symbol -- and needed a HUGE battery.

The Minolta cameras that used it also carried the "atom" on the front plate -- as seen in the photo from monopix (above).

Starting with the Hi-Matic G, Minolta moved to a much simpler system that only needs a 675 battery.

Still it might have a gummed up slow speed escapement, but it's probably inside the lens.

 

[monopix]

To add...

My mistake, that's an F not a G but the shutter is the same as far as I know.

The fact it only sticks at wide apertures/slow speeds suggests the blades or driving mechanism are sticking at the point the shutter becomes fully, or near fully, open. I think you need to open it up.

 

[monopix]

That photo is from a Hi-Matic F which is completely different from the Hi-Matic G. The Hi-Matic F, and some other Hi-Matics, used an electronic shutter based on the famous Yashica electronic shutter -- and needed a HUGE battery. The Hi-Matic G has a much simpler system and only needs a 675 battery.

Still it might have a gummed up slow speed escapement, but it's probably inside the lens.

Yes I think it is an F but the shutter is the same. At least, the principle of it is the same. The F did NOT use the same shutter as in the Yashica and it didn't use a 'huge' battery.

 

[monopix]

I don't know this camera or shutter, but based on the image posted by monopix, it looks like a typical mechanical slow speed escapement is part of the shutter. Based on what you say is happening, I'd expect that the escapement is gummed up or such, causing the very slow release.

It's not a slow speed escapement as in the usual sense. The escapement slows the opening of the shutter so that the degree by which it opens is determined by the time allowed. That way, both shutter speed and aperture vary together with a single control. It's very simple but quite a clever way of achieving aperture and shutter speed control together.

 

[xkaes]

I've downloaded the Hi-Matic G Service Manual from LEARN CAMERA REPAIR and, as I suspected, the shutter is completely inside the lens housing. That pretty much requires a complete break-down. I'll examine it more in detail -- the step-by-step instructions (with exploded diagrams) are very complete -- when I have the time, and decide if it's worth my time.

If anyone would like a PDF copy, let me know.