Bronica etrsi shutter probs

millboyold · Aug 5, 2025

Hello All, wondering if anyone can help.
My Bronica etrsi has defaulted to 1/500th unless I attach the AE11 prism, and set the prism to Manual. I have tried 3 different lenses, all with the same result. I have cleaned the contacts on the camera and lenses, I have replaced the battery twice, and confirmed the battery is reading 6.5 volts. I fear the camera is sending no signal to the lens, but can't understand how attaching the prism allows the shutter selection circuit to work . I was hoping these symptoms may characterise a particular fault. I dont really like framing via the prism, and, being ancient the angle of view via the waist level finder is more comfortable when using a low viewpoint.

Thanks Jim Halett

PS Just discovered that the manual shutter selection works even if the prism is switched off, it just has to be attached to the camera ....weird.

MattKing · Aug 5, 2025

Did the contact cleaning include the contacts with and on the prism and the film back?

millboyold · Aug 5, 2025

Hello Matt, thanks for the reply, there are no contacts on the film back, but yes I did clean the contacts on the top of the camera where the meter and the camera meet. But as I said the shutter selection works with the prism attached. It dosen't even have to be switched on, (the prism), so there is no problem there. The problem is that with the waist level finder on it only fires at 500th.

reddesert · Aug 6, 2025

I certainly don't understand this, but it seems likely that something about attaching the prism is allowing the camera to send voltage to the body-lens contacts, and that with the prism detached, it's not putting a signal on the body-lens contacts, so the lens is firing at the mechanical speed.

Both the ETRS and the ETRSi repair manuals discuss that attaching the AE prism depresses a pin that switches control over the shutter speed circuit, I don't quite understand how this interacts with turning the prism off and using the camera on manual, but you might want to look there for a start.

BMbikerider · Aug 6, 2025

millboyold said:
Hello All, wondering if anyone can help.
My Bronica etrsi has defaulted to 1/500th unless I attach the AE11 prism, and set the prism to Manual. I have tried 3 different lenses, all with the same result. I have cleaned the contacts on the camera and lenses, I have replaced the battery twice, and confirmed the battery is reading 6.5 volts. I fear the camera is sending no signal to the lens, but can't understand how attaching the prism allows the shutter selection circuit to work . I was hoping these symptoms may characterise a particular fault. I dont really like framing via the prism, and, being ancient the angle of view via the waist level finder is more comfortable when using a low viewpoint.

Thanks Jim Halett

PS Just discovered that the manual shutter selection works even if the prism is switched off, it just has to be attached to the camera ....weird.

It may be a circuit fault inside the camera body which is being by-passed by the inbuilt internal circuit in the eye level prism. If it is working correctly with the prism on, then it may be repairable. Bear in mind these all electronic cameras will be approaching at least 25 years old and may never have been serviced.

skahde · Aug 6, 2025

BMbikerider said:
It may be a circuit fault inside the camera body which is being by-passed by the inbuilt internal circuit in the eye level prism.

If I extrapolate from my GS-1's, I suppose the connections from the electronics in the body to the contacts in the bayonet are interrupted, while the connections from the body to the prism and from there to the bayonet are fine. Time to look inside the body and search for bad soldering or corrosion. Nothing I would like to delve into on a camera.

millboyold · Aug 6, 2025

Thanks all.
In a modern electrical circuit I would suspect a blown switching transistor in the body that has stopped reacting to the changes in current pathways when the prism is detached. The maual does show a "prism switch" in the body which might just be a solinoid,( I have tested this theory with violent shaking!) After trying to repair a Bronica lens shutter I agree with Skahde, not a relaxing pastime.
Though I feared the worst I was hoping it was something simple. Oh well think I'll stick to the prism. Thanks Jim

millboyold · Aug 6, 2025

Hello all, it is fixed (for now). Prompted by Reddesert I looked into the AE pin switch. Mine appeared to be working fine, but there must have been some build up of detritus at the bottom (within the camera). I ran some alchahol down the pin and it seems to work now. Thanks all
Jim hallett

neilt3 · Aug 6, 2025

millboyold said:
Hello all, it is fixed (for now). Prompted by Reddesert I looked into the AE pin switch. Mine appeared to be working fine, but there must have been some build up of detritus at the bottom (within the camera). I ran some alchahol down the pin and it seems to work now. Thanks all
Jim hallett

Good to hear , and thanks for updating this thread .
I also have an ETRSi and an ETRS , both are fine now , but worth knowing of this problem and a solution should it occur on mine .

skahde · Aug 6, 2025

millboyold said:
Hello all, it is fixed (for now). Prompted by Reddesert I looked into the AE pin switch. Mine appeared to be working fine, but there must have been some build up of detritus at the bottom (within the camera). I ran some alchahol down the pin and it seems to work now. Thanks all
Jim hallett

Congratulations! Nothing more satisfying than a successfull troubleshooting!

reddesert · Aug 7, 2025

millboyold said:
Hello all, it is fixed (for now). Prompted by Reddesert I looked into the AE pin switch. Mine appeared to be working fine, but there must have been some build up of detritus at the bottom (within the camera). I ran some alchahol down the pin and it seems to work now. Thanks all
Jim hallett

Great, and thanks for posting the update - may help some future person searching for a similar problem.

In my experience with low-voltage electronics, problems are more often something electro-mechanical, like a dirty/oxidized switch or contact or a degraded solder joint, than the actual failure of an electronic component. There are a few cases of components that are known weak points (such as certain 80s cameras with capacitors that fail), but I try to look at the electromechanics - this happens in other fields as well, such as musical / amplifier electronics.

flavio81 · Aug 22, 2025

reddesert said:
In my experience with low-voltage electronics, problems are more often something electro-mechanical, like a dirty/oxidized switch or contact or a degraded solder joint, than the actual failure of an electronic component. There are a few cases of components that are known weak points (such as certain 80s cameras with capacitors that fail), but I try to look at the electromechanics - this happens in other fields as well, such as musical / amplifier electronics.

Agree.

Bronica etrsi shutter probs

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