AE-1 Firing early - when I press the shutter halfway to meter light, it takes a photo

RockandGrohl · Oct 21, 2015

This is an incredibly irritating issue and I'd love some help.

I have an AE-1 that I adore, it's in such great condition, but unfortunately it's developed a really quirky fault.

It started after a 45-minute exposure, the next day I took it out again and tried to get a shot. It locked the shutter release, which stopped me advancing the film, and it stayed like this for about 2 minutes (while I was frantically de-coupling the lens, pressing buttons, trying to unstick my camera) while I was looking at it in my hands thinking "The hell do I do now?" the mirror flipped back down of its own accord and I could use the camera again - with one catch - whenever I have cocked the camera and am metering the light, the damn thing fires.

Has any body run across this before? I've just tried it with a spare battery and it is still showing the same issue unfortunately.

Thanks,
- Chris

AgX · Oct 21, 2015

"Hiatus Preacox Canonis"...

Welcome to Apug!

My first thought is a faulty shutter switch. The locking you describe then makes sense, if you still had set the shutter to "B".

Are you shure it is releasing "halfway"? Or just releasing without plain metering first?

I think there is not much between that switch and the IC. Thus I guess it either is that swicth or the IC.

Chan Tran · Oct 21, 2015

How did you do the long exposure? Put in on B and use a locking cable release? In that the cable release may have damaged the shutter release button.

AgX · Oct 21, 2015

A release switch should be designed to withstand "normal" pressure on its dead end.

John Koehrer · Oct 21, 2015

AgX said:
"Hiatus Preacox Canonis"...

Welcome to Apug!

My first thought is a faulty shutter switch. The locking you describe then makes sense, if you still had set the shutter to "B".

Are you shure it is releasing "halfway"? Or just releasing without plain metering first?

I think there is not much between that switch and the IC. Thus I guess it either is that swicth or the IC.

I'd agree with AgX's assessment. A fault in the switch. The switch in this camera is three layers of gold plated brass separated by layers
of PC board material & held together with one screw.
I've seen the problem here & there but can't recall the solution,

RockandGrohl · Oct 24, 2015

Chan Tran said:
How did you do the long exposure? Put in on B and use a locking cable release? In that the cable release may have damaged the shutter release button.

Hi, yeah now that you mention it, I propped the camera up and had it in B, with the shutter in, had it going for 45 minutes. When I was done I remember struggling to get the cable to unlock, so that may have damaged something :/ stupid cheap chinese £2 cable from amazon!

pauliej · Oct 24, 2015

Did you check the camera instruction book to see if you did the long exposure correctly? There could be a sequence of events and you missed some step - just a thought. I hope you get it fixed.

paulie

AgX · Oct 24, 2015

There is nothing special to the bulb setting at the A-cameras.

RockandGrohl · Oct 25, 2015

Opened it up today hoping to gut my squeaky smelly AE-1 and use the shutter switch in my current AE-1. Looks like that's a no go - the shutter switch is attached to a wafer sheet of circuit paper so I can't swap the switches over. Something definitely doesn't look right about the shutters though - The malfunctioning shutter switch has three layers of metal sandwiched in between some non-conductive plastic. When the top layer touches the middle layer, the camera fires. What's supposed to happen is the top layer touches the middle layer and that's supposed to trigger the light metering. Then when you press those two layers down to meet the third, it fires the camera.

On my squeaky AE-1, the bottom layer is very almost touching the middle layer. On my malfunctioning one, it was pushed down past a retaining clip. But after having bent it roughly back into shape and putting the camera back together, it still behaves as it did before.

Video incoming where you can see exactly what I mean.

RockandGrohl · Oct 25, 2015

https://youtu.be/nExp_QtE49o

AgX · Oct 25, 2015

At least that excludes the shutter as a cause (like grain of sand between contacts).
Still there can be a shortcircuit after the shutter or an fault at the IC.

Try to check the wiring up to the IC. If you can't find anything suspicious use that camera for parts... the good ones...

John Koehrer · Oct 25, 2015

You understand how the switch works. Good!

On to another possibility though. AE1 uses a solenoid to release the shutter. One of them is visible by removing the bottom cover.
It's under the winder linkage and usually has blue or green insulation around the coil. I't held in place by one screw. I've cleaned the contact with a strip cut from the edge of a dollar bill wetted with alcohol.
I don't remember if it needed to be unsoldered or not and you may need to lift the linkage held in place with a tiny "c" clip.

AgX · Oct 25, 2015

How could that premature releasing be linked to that solenoid?

shutterfinger · Oct 25, 2015

Remove the top housing. Now press the switch as you did in the video and observe the switch contacts at the front side of the screw that holds the contacts in place. 2 contacts 3 as 1 contacts 2. Reform or further insulate the contacts at the screw to just in front of it.

John Koehrer · Oct 26, 2015

AgX said:
How could that premature releasing be linked to that solenoid?

I misspoke. It's a relay not solenoid. Sometimes it's called "release magnet". If it's not holding or, if it's stuck and the camera is wound
that may release the shutter on advance.

It;s been far too many years since I've dealt with these accurately but it's in the flow chart.
After I replied & thought about it, It could even be on the other end of the camera.

But it's visible when the bottom cover's removed.

RockandGrohl · Oct 29, 2015

John Koehrer said:
You understand how the switch works. Good!

On to another possibility though. AE1 uses a solenoid to release the shutter. One of them is visible by removing the bottom cover.
It's under the winder linkage and usually has blue or green insulation around the coil. I't held in place by one screw. I've cleaned the contact with a strip cut from the edge of a dollar bill wetted with alcohol.
I don't remember if it needed to be unsoldered or not and you may need to lift the linkage held in place with a tiny "c" clip.

I'll have a look on the weekend, thanks!

RockandGrohl · Oct 29, 2015

John Koehrer said:
I misspoke. It's a relay not solenoid. Sometimes it's called "release magnet". If it's not holding or, if it's stuck and the camera is wound
that may release the shutter on advance.

It;s been far too many years since I've dealt with these accurately but it's in the flow chart.
After I replied & thought about it, It could even be on the other end of the camera.

But it's visible when the bottom cover's removed.

Oh is that the electro magnet? So would you advise undoing the bottom of both my AE-1's and monitoring both when I press the shutter button to see if the faulty AE-1 is exhibiting anything on the bottom end?

John Koehrer · Oct 29, 2015

^^You can watch it but may not see anything, the contact moves pretty fast.
I just took a sliver from the end of a bill, wet it in alcohol, threaded it between the armature & coil, put a little pressure on it
& drew the strip out. Repeat it a couple of times and you MAY have a working camera,. Or not.

Chan Tran · Oct 29, 2015

I see John! The solenoid is to hold the shutter curtain and if it doesn't grip tight enough it can cause premature release.

AgX · Oct 30, 2015

But what has this to do with the camera releasing at 1st step of the release button? Why should any solenoid malfunction just arise then?

AE-1 Firing early - when I press the shutter halfway to meter light, it takes a photo

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