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    AST RESEARCH, INC.          TECHNICAL BULLETIN #0147                  1-13-95

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                   ASCENTIA 900N EASYPORT II AND EXTERNAL PS/2 MOUSE

    PROBLEM:        While connected to an EasyPort II, the Ascentia 900N system
                    may not recognize an external PS/2 mouse.  If the Ascentia
                    900N is powered down and a printer is left with power on, the
                    next time that power is applied to the Ascentia 900N, the
                    external mouse fails to be recognized (intermittently), and the
                    integrated pointing device becomes available instead.

    CAUSE:          There is a voltage leak on the EasyPort II caused when the
                    printer attached to the EasyPortII is ON.  The leakage occurs
                    in the DOCKER CHIP location U6 (AST P/N 239020-001), as well
                    as the HC125 drivers in locations U4 and U7 of the
                    EasyPort II.  When this leakage occurs, there is about 2.0V on
                    the EasyPortII as well as in the Ascentia 900N.

                    The Hardware Mouse (PS/2 type) performs its internal reset via
                    the +5V (power) line.  The reset depends on the +5V supply to
                    go from ground to +5V (+/- 10%). The "GROUND" level should be
                    no higher than 1.0V / 1.2V, to guarantee proper hardware reset
                    to the mouse hardware.

    SYSTEMS
    AFFECTED:           AST
                    PART NUMBER     DESCRIPTION

                    500974-XXX      EASYPORT II

    SOLUTION:       Do not leave the printer ON when the Ascentia 900N is turned
                    off while connected to the EasyPort II.