I did a little more digging. Apparently, Compass Electronics goes back to at least the 70s. This is probably when your unit was built But they fell on hard times, and a fire finally wiped them out, somewhere around the 90s.
One of their former metal detector techs bought the rights to their name, and began servicing their metal detectors in Europe. Eventually, he re-opened Compass in 2002. And now they're gone again.
But this would explain why all of the references to Compass on the web point to only their metal detectors. Wasn't any Web back in the 70s!