Bernina sewing machine, maintenance?

#1

I gave this a test run last night, repairing a canvas bag. It runs very well. A lovely machine :smile:

Semi-Industrial Sewing Machine - Bernina Favorit 740
Semi-Industrial Sewing Machine - Bernina Favorit 740
#2

I had a go over the weekend with less success.

The main issue seemed to be with the bobbin side of things; the mechanism was sticking with the needle close to top-dead-centre and the result of moving through was a horrid tangle underneath the work surface.

I initially suspected the needle but as the stick was with needle up the thread doesn’t really flow then. Possibly the thread was too thick but it was only general purpose 3ply cotton.

I did label some of the controls
I also encourage anyone of a mech eng bent to have a squiz inside (look)
Bobbin sits like this

image.jpg3264×2448 1.09 MB

Some controls
image.jpg3264×2448 1.17 MB
image.jpg3264×2448 1.34 MB

image.jpg3264×2448 1.25 MB

#3

It might just need lubricating. It has been stored in a dusty room for a while, after all. The manual (see above) indicates where the oiling points are. We just need some light machine oil.

#4

I saw that. The only oil I could see was 3-in-1 which I though would be inappropriate. Lots are packet atm

#5

Hello. Anyone up on Bernina 730 Record repairs? I’ve done some on mine, notably replacing the cam stack gear, but need more information. Specifically about the sleeve you have to pull down to do buttonholes. Mine is stuck. Can it be repaired?