The 348 is belt driven, double belt driven, actually. There's a timing belt under the bed. So if it gives you trouble, that belt might need replacing.
Aside from my mother's Pfaff 1222SE (1980's), the 348 is the only machine I've had professionally serviced. I was thinking about giving it to a friend and wanted to be sure it was sound. That second belt made me extra cautious, as I've never worked on a machine that had one.
Too cute to give away. I'm still thinking about it.