On second look I'd call it as a 1992. From memory this was the first year they used that style decal for the top tube and last year they had the front mech cable routed along the down tube. This would also date the LX gear as period correct.
A 1990 would have a shorter head tube and the seat stay would meet the seat tube lower then the top tube instead of in-line like yours. I've got a 90 and 93 listed below for reference.