Mainframe is a G.I. Joe team operative in the A Real American Hero line. First released as a Hasbro carded action figure in 1986, with 2 distinct figure versions produced across the 1982 to 1994 vintage run.
Mainframe appears in 2 episode synopses across the Sunbow (1983 to 1987) and DiC (1989 to 1992) runs, first appearing in Sunbow's "Computer Complications" (1986). Full screencap and continuity review pending.