The pictures I found seem to indicate this is one of the gazillion sewing machines produced in Japan starting after WW II. I think they're generically referred to as Japanese Zigzaggers and most of them were good machines.
You almost certainly have a hook timing issue. And I wonder if your feed dogs are down. It sounds like you're familiar with sewing machines so you probably know that many machines drop the feed dogs to allow darning and free motion work.
Definitely, pictures. Needle area, bobbin area with the cover off, a look behind the front needle bar cover. A peek under the top cover wouldn't hurt. And, how about that underside, while we're at it. This way we can get a good idea exactly what kind of machine we're working on and hopefully give better suggestions.
I'd also recommend you to the Quilting Board forum, in the vintage sewing machine section. They're pretty dedicated domestic sewing machine people over there.
It's quite likely this machine can be restored to working order unless it's missing some critical part.