From the similar thread about vintage Japanese machines with fancy stitches: post 134 by Susanmarie shows a picture and offers some info about a Coronado badged machine.
She pointed to a free manual (thank you!) on the Singer site (White 231). It looks VERY similar to the following pictures on this thread if anyone is missing a manual:
165 Lew Schiller Universal
234 LynxSS Sewmatic
287 Soman2 McKee Dressmaker
301 Manalto Rotary Electric
I was interested because I have an American Beauty that is also a match (doesn't take cams - like the Rotary at 301). The manual for the White 231 shows cams so I'm not sure if mine is an older model or maybe at a lower price point. But the rest of the pages seem relevant. I can't use mine until I replace the cord. : (