Quiltingboard Forums - Bernina 730 Record Service Manual?

That stitch width selector is probably froze up. You need to remove the center, needle bar position knob. But f you pry on the knob, you can break it. If you turn the knob to the far left, you'll see a hex shaped screw on the right side of the mechanism. You need to loosen it, then carefully pry from the inside. When it gets a little movement, tighten the screw and push it back in. Loosen the screw, pry, tighten the screw, push back in... until you get the center knob out. If you can't get them apart, heat helps. If you can get the knobs off together, put some water in the microwave until it comes to a boil (I usually go 3 minutes). Then put the knobs in the water to get them good and hot. While they're hot, they'll come apart, then you can clean them up.

There's also a spring loaded pin that rides on the needle position.... thing (don't know the name). If that's gummed-up, you don't want to push it in, or it won't come out. Work some solvent into it, then gently grab it with wire cutters or tin ships, and pull it outward.

Camstack gear is tricky. I haven't actually done the whole thing myself. The parts I do know are... Get violent, and break the old gear off with a screwdriver. Then the front dial and assembly has to come off. There's a hole in the back of the machine that you push the shaft forward to get it out. We've got a tool to hold all the cams together in their position, but you could just wrap wire around the stack. There's a design inside the camstack to help you keep them in order. And if you don't get the worm gear underneath lined-up correctly, you'll throw off the parabola. You can get your sewing machine repair shop to order you a new camstack gear from Brewer for about $34.

I'll bet there's a YouTube video on how to do this...