William E. Maya, 39, president and a...

William E. Maya, 39, president and a director of Birtcher Corp., El Monte, has been named to the additional post of chief executive. Daniel P. Whelan, 38, has joined the electronic medical instrument company as vice president and chief financial officer. Robert H. Colgrove, 37, has been named vice president-operations. Maya succeeds Ronald E. McAdams, who has resigned as chief executive, chairman and chief financial officer but who continues as a director. The chairmanship will remain open for now. Whelan previously was vice president, chief financial officer and corporate secretary for Wespercorp of Irvine. Colgrove, previously vice president-operations at Pilling Co. in Ft. Washington, Pa., succeeds Ernest V. Jarvis Jr., who has resigned.