A genuine Bernina cabinet is hard to find, and if I should ever require one I would have to jump at first chance. They turn up now and then, but even rarer in my area. I didn't know this until a couple of years ago, but Bernina made treadles up until around 1960, when exactly production stopped I'm not sure.
The hand wheel on them is different, other wise the same. The ones I have seen have often had an external belt driven motor in the back, for easy coversion to treadle. I'm in Norway, and I have noticed they are more common in Germany and Austria (more people there). I don't think the production was particularly aimed at Amish in general, but I guess they might have been intersted in them.
It's a bit odd it's often the 540 and 740 that's in treadle cabinets, they are built for more speed and power than the others. Treadle is not where this kind of speed enters the picture. People still had experience, very good technique and new the advatage of a treadle back then. I guess that's why these combo cabinets excist and are still appreciated.
If it was me, I would not hesitate to get a leather belt and try it out. The motor belt should come off easily and come back on just as easy.
Last edited by Mickey2; 11-29-2017 at 09:58 AM.