Amdahl Corp shares were down 4.8% in active trading on the American Stock Exchange yesterday morning after Shearson Lehman Brothers Inc analyst Donald Young downgraded his investment rating and slashed earnings estimates for Amdahl to reflect his forecast of losses in the first two quarters and a slower-than-expected increase of deliveries of new 5995-M mainframes – We have recently contacted a customer scheduled for an early delivery of the new Amdahl 5995-M mainframe, Young told Shearson’s sales force – In the last week, Amdahl slipped delivery from December to April; according to the customer, there are apparently technical problems with the 5995-M that need to be resolved; Young advised clients to switch to IBM Corp from Amdahl, but IBM shares were shading down too.