Problem p5000etch SNF 2010-05-13 19:54:42: DC bias unstable on ch. B

ran 2 wafers, "ch. B Jim-ox" yesterday and DC bias was stable: ~ -450-500V.
ran 10 wafers, "ch. B. Jim-OX" today and 8 of 10 wafers had unstable DC bias ranging from -500V to +50V, roughly.