Technical question regarding 35 GTN

[Irish RF User]

Hi all, I have been browsing these forums for some time now and after purchasing my first rangefinder camera decided it was time to sign up

I have got hold of a Mint Electro 35 GTN and I have to say I like it a lot, it has some great features for street shooting such as the exposure warning lights on the top plate and the fact that it's inexpensive so I don't have to woory about it too much in certain areas

Everything is working fine on the camera but it does have one itermittent problem. At random times the shutter will not stay open for the correct amount of time. I can over come this issue if I keep the shutter button fully depressed during exposure so this I imagine would point to the fault ?

The shutter fires correctly everytime on the flash speed, I can tell by the sound as it is much slower. The camera also works perfectly using the Bulb setting. I did find an older thread on here where someone had a similar issue but their camera would not fire on bulb, mine does.

It's not the end of the world as I can keep the shutter button depressed during exposures, 99 percent of which are fast anyway, Daylight with Tri-X but it is something I would like to fix if possible.

I have checked the POD and it's perfect. I have also tried adjusting the shutter release, screws under the base plate but it changed nothing.

Any ideas ?

[Irish RF User]

Ok, just after typing my post I took a look at the camera. I have just fired the shutter a number of times and just realized The shutter is only intermittent when the camera is vertical, if I tilt it forwards or backwards it fires 100%

[btgc]

I had similar issue (just I haven't tried rotating or tilting camera) with shutter times being sufficient only when keeping release depressed. Years ago I've written a post here on RFF, and some other people also have dealt with this. Adjusting rod under bottom cover is of help. Sorry I'm not looking up exact references.

[ColSebastianMoran]

Shutter staying open long enough... This is an electronic shutter; an electromagnet holds the shutter open. If the shutter won't stay open, then there's a failure in getting current to the magnet to hold the shutter open. Could be lots of things.

Happens if you don't hold down the shutter button. Yes, I've seen that on a GSN I owned.

What to do? Maybe cleaning switch contacts or resoldering a wire or adjusting the rods or replacing the POD, all these can be done by mere mortals. If it's a circuit board problem, that's harder. Mark Hama in Atlanta has the parts and the knowledge.

If it's working well in other respects, I would probably get used to holding down the button.

[ColSebastianMoran]

Originally Posted by Irish RF User

... I did find an older thread on here where someone had a similar issue but their camera would not fire on bulb, mine does.

Probably the thread started by me. I got lots of advice, some contradictory. In the end, I sent the camera to Mark Hama and it came back working perfectly.

[elmer3.5]

Hi, since it´s elecrical try to load some new batts, the other thing that happaned to me was the shutter not reaching fully it´s position when releasing it, i had to take of the top of the camera and screw back in place the little rod that links the button with the shutter mech.

Great camera you´ll find it´s super sharp!

When you need over or under exposure you can compensate moving the asa iso settings, for instance you over expose with 400 iso and you set 200!

Bye!

[stratcat]

If you're REALLY into DIY you can try troubleshooting the circuit yourself. You could start with this secion of the repair manual.

Otherwise you might want to send it to either Mark Hama or camerarefurb.com

There's always the option of buying another one.

[Irish RF User]

Originally Posted by btgc

I had similar issue (just I haven't tried rotating or tilting camera) with shutter times being sufficient only when keeping release depressed. Years ago I've written a post here on RFF, and some other people also have dealt with this. Adjusting rod under bottom cover is of help. Sorry I'm not looking up exact references.

The tilting the camera thing was random, it's doing it at all angles now

Originally Posted by ColSebastianMoran

Probably the thread started by me. I got lots of advice, some contradictory. In the end, I sent the camera to Mark Hama and it came back working perfectly.

Yes that was the thread I was looking at. Mark Hama sounds like a good guy to repair these but I am in Ireland so that rules that out.

Originally Posted by elmer3.5

Hi, since it´s elecrical try to load some new batts, the other thing that happaned to me was the shutter not reaching fully it´s position when releasing it, i had to take of the top of the camera and screw back in place the little rod that links the button with the shutter mech.

Great camera you´ll find it´s super sharp!

When you need over or under exposure you can compensate moving the asa iso settings, for instance you over expose with 400 iso and you set 200!

Bye!

The battery is definitely not the issue, have tried different types new and older. I am going to have another tinker with it today. I think the main problem is lack of use, it's probaly been sitting around for decades not getting to take any photos and is now all moody because of it. I think cameras are like cars, best not left unused

The higher film speed settings on the later models are one of the main reasons I wanted one as it allows for a better range of exposure compensation, thats all an exposure compensation dial does anyway, change the film speed so as to fool the meter.

Originally Posted by stratcat

If you're REALLY into DIY you can try troubleshooting the circuit yourself. You could start with this secion of the repair manual.

Otherwise you might want to send it to either Mark Hama or camerarefurb.com

There's always the option of buying another one.

Yeah I like a bit of DIY but I am not the best with electronics, hopefully it's a mechanical issue.



I am going to Strip it down a bit today and see if I can work out the problem.

From looking at the online service manuals it looks like the shutter is tripped mechanically by a lever so once tripped I can't understand why releasing the shutter button sometimes ends the exposure prematurely. I know the shutter timing is electronic but is there any electrical connection between the shutter button and the shutter ? if I use the self timer it fires correctly every time so I don't think its an electronic problem with the timing ciruits etc.

[ColSebastianMoran]

Originally Posted by Irish RF User

From looking at the online service manuals it looks like the shutter is tripped mechanically by a lever so once tripped I can't understand why releasing the shutter button sometimes ends the exposure prematurely. I know the shutter timing is electronic but is there any electrical connection between the shutter button and the shutter ?

Yes, the shutter button moves a rod or rods which is part of a slide switch, that's the electrical connection.

[Irish RF User]

Ok, I think i have discovered the solution

There is a small electrical tab on the bottom of the small tracked circuit board that should contact and stay in contact with what I think is the exposure meter finger that gets pushed downwards with the shutter button.

These fingered contacts position and range of travel are determined by how far the larger shutter control screw underneath the baseplate is screwed in or out. I tried many times before dismantling the camera to adjust this larger screw but no matter what position I tried it in I would nearly always have to keep the shutter button depressed to complete the correct exposure time.

On dismantling the camera so I could gain access to the shutter control rods I could see that with the larger shutter control rod in the correct position to latch on firing the shutter, the meter electrical contact finger ( at least I think it's the meter finger ) was just short of making a connection unless I kept the shutter button fully depressed.

I couldn't screw the rod any further clockwise as it would then not latch when the shutter button was pressed. I then realized the small circuit board has some play in it's two mounting screws and this has allowed me to shift it to a better position so it does make contact.

My guess is due to thie play in these mounting holes some of these cameras may have been assembled with this board in just to low a position leading to this problem, or it might have shfted over the years from the pressure of the shutter button and it's springs ..........................at least I hope so anyway.........we will see

Going to solder the few wires I had to disconnect back up now and hope this solves the problem.

Fingers crossed, could all be in my head afterall

[Irish RF User]

Success

It is now working perfectly, exposes for the correct time everytime, well so far anyway, but I must have fired it well over a hundred times. I was also able to adjust the smaller screw to give a smoother feel to the shutter button so all in all I am chuffed

Tomorrow I will glue the covering back and replace the badges and then it's time to put a roll through it for the big test.

I will take a picture of it also and post it up.

[ColSebastianMoran]

Bravo. Nice work.

[stratcat]

Congratulations!

[Irish RF User]

Here are a couple of pictures of the offending camera.

Putting a test roll through it tomorrow, FP4 as I want to save my Tri-X for the real stuff.