I have 4 Pfaff 7570's and they do have batteries, 2 in the bottom, but here is the thing the batteries are for keeping the memory for your patterns, I took mine out, and the light comes on each time I turn on my machine saying to change the battery, no worries I just push button for the stitch I want to do and away we go. I do not have the designer, (well I do have one but have no idea how to use it, and do not have a computer old enough to work with it! ) so no need for the battery's. When I want to do embroidery I just pop in one of the cards and it works just fine.
If you need another I hope you can can find one, it would be so worth it, the older Pfaff's are wonderful machines and I would not part with mine! good luck, I have a great repair man here in western KY, but might be too far for you to ship your machine. (had a 7570 shipped to me from TX and it arrived broken, not worth getting it fixed, so be super careful if you ship it)