It is all mechanical, pre-computer Asian made machine for sure. It appears to have some kind of cam stack inside for changing stitches. You will need to clean the inside and outside. You will need to figure out how the knobs and levers all work. Go slow, clean then oil everything. While yours isn't terribly fancy, here is a link to a thread about the Japanese zig-zag machines with fancy stitches you might like to look at:
http://www.quiltingboard.com/vintage...s-t207877.html
whoops that was the wrong one but I left it anyway
here it is:
http://www.quiltingboard.com/vintage...s-t207880.html