How To Get Into The Top Of A Bernina 930

There are two spring-loaded screws on the top of the machine.  One on the right (under the bobbin winder lid), and one on the left (built into the bobbin winder tensioner).  Push down, then turn a quarter of a turn.  You'll know you're in the right position if the screw pops up.

Once you get inside, you can clean and oil, and adjust the presser foot tension.  Here's where that adjustment is.

The copper colored cylinders are the basting mechanism.  Be sure to use this feature every-once-in-a-while, so it doesn't freeze-up.