I am glad you are making sure the wiring is in order before giving it to your DD. DH always checks and repairs all the vintage machines we buy so I am not sure what to do.
You might also want to remind her to be very careful of the little light that is attached to the machine. You can get really burned by it. I have heard of people not using that light but using an additional source to light the work area. I have had some issues because I grab the little machine through the center opening and my arm or fingers hit the light.