Apple Computer Inc lost another long-term employee yesterday after the head of its battered PowerBook division, 11-year Apple veteran Brodie Keast, was replaced by Dale Fuller, formerly NEC Technologies VP of laptop computer products. Keast went on sabbatical six weeks ago (CI No 2,953). Apple said it tried to find a place for Keast at the firm but nothing suitable arose on either side. Fuller worked in Apple’s business development group from 1987 to 1991.