The New Yorker who imported Italian made Necchi sewing machines in the late 50s decided to make a machine on his own. He had these made in Japan, which normally means a well made machine. Necchi sued as the name he was using was way too close to Necchi and the machines are not in any way Necchis or related to them. I think Nelco was the new name he chose.
I'd get the tension worked on one time. These old Japanese machines are workhorses, as previous posted have indicated.