The blond birch/beech root veneer on that cabinet is utterly stunning, I keep going back to the German ebay ad to look at the photos! It looks more like an elegant drinks cabinet than something built to house a sewing machine. Gorgeous. I had no idea the vintage Bernina cabinets are so utterly beautiful
Arrow thank you for enlightening me!
I think I may have worked out what the issue is with the 840 regarding the stitch width knob, although I could well be wrong as I am obviously not a Bernina tech just someone who knows very little but enjoys playing around with the insides of sewing machines
I don't know what the proper names are for the parts I am talking about, and my account is rather rambling, so please forgive me for that. If anyone can shed more light on what I am trying to fix here I would be very grateful!
I had a good look at my little Bernina 807 minimatic, and the stitch width knob set-up on it looks to be more or less the same as on the 840.
It seems to be essentially a slider mechanism, consisting of a channel and a sliding 'block' which slides up and down the channel. The 'block' connects to a linkage attached to the needle bar, so as the block moves up and down the slider channel - when the stitch width knob is moved - the needle bar moves correspondingly from side to side.
At 2 points in the channel on the 807 there are 2 drilled-out 'circles', and I assume that some kind of raised 'peg' which protrudes from the sliding 'block' clicks into these circles, such that the pre-set buttonhole stitch widths can be selected on the 807 (- which does not have the buttonholer dial of course). You can hear and feel the 'click' as the 'peg' clicks into each circle.
In between the circles the slider is flat, but the 'peg' or whatever it is, I assume (- I could be wrong though) must protrude such that the 'block' can nevertheless be held in place at whatever point on the flat channel you select (-by turning the stitch width dial), by the 'peg' pressing on to the slider channel's flat surface (?).
On the 840, although I can see a circle towards the top of the slider channel, (- the same as on the 807), there is no 'click', so I assume that there is some kind of problem with the 'peg'. Also since the knob bounces back to 1 when you turn it, I suspect the 'peg' does not touch the channel at all (?).(I could be totally completely and utterly wrong here...
)
2nd EDIT TO ADD: yes, after a rethink, I think I was totally wrong...
I'll see what more oil, heat, and patience will do.
Here's a pic of the parts I am taking about, with an arrow pointing to the slider channel, and another to what I assume is the 'peg'. The 3 other bits inside the circle make up the sliding block.
[edited because I got my words mixed up...]