Thanks, David. If I can get access to actually see the shutter mechanism, it may well be something simple as you say. After all, it fires at about 1/60 and opens on bulb. I think there is more to it than removing the glass, however - I think the chrome metal on the front has to come off somehow. But I'll probably try; nothing ventured, nothing gained. And Flutot hasn't responded to my email of the other day.