1937-1947. Founded by Dickerson Brothers in 1937, lap steels and small amps. Also made amps for Oahu and Gourley Brands. 1947 changed ownership and renamed Magna Electronics (Magnatone). [Source: Vintage Guitar Magazine Price Guide ]
Image ebay: Plate on back reads:
FATORS MFG. CO.
3998 SO. VERMONT AVE.
LOS ANGELES 37, CALIF.
110-120 V. AC 50-60 CYC.