I actually worked at Draco Labs making these (they were assembled by hand) in 1979. Draco, which was Larry Shotz's first company, designed and built them, but had an agreement that they were initially distributed by Sherwood, then still in Chicago. The physical case was identical to a matching Sherwood integrated amp (which was 100 w /channel and cost something like 1/3 of the tuner, which did retail for $2000). After the falling out, we simply used mineral spirits to rub off the sherwood name, leaving
"micro CPU 100" silk screened on the front.
The tuner was a beast and weighed 36 lbs. And correct another post, it was not marketed by Crown. Draco labs designed and built Crown's FM-1 under contract. Draco was in Grafton, WI and Crown, Elkhart IN, so the Crown people drove up in a van to grab units as we made them (which I assembled as well).
I had a unit that I build after hours that larry let me buy for parts cost. The tuner required a number of hours on the test bench for calibration after assembly and the tech that did that, a guy named Mike, spent extra time tweaking mine. Supposedly it had some of the best specs of any that came off the line.