I can offer no specific information other than to say the Brand suddenly appeared in just one store here in the late 1970s, a store that stocked only premium brands.

It purported to be a premium product at relatively low prices - it wasn't a wide range and didn't sell well and disappeared in the early 1980s.
I have a suspicion they might have been "label engineered" Sanyo products. Perhaps it was thought Fisher was a more acceptable name in western markets.