Date   : Sat, 19 Apr 1986 16:41:17 EST
From   : Eric Stork <STORK@mit-mc.ARPA>
Subject: Simple KAYPRO Fix

KAYPRO owners should be interested in a frequently-occurring
harware problem, and in a simple, virtually no-cost cost fix.

    .   I learned about the fix from Ray Kester of
        Springfield, VA, to whom I'd been referred for help
        in fixing the KAYPRO my son uses in college.

    .   Ray suggested that before I bring him the unit, I
        check what he had discovered to be a very frequent
        problem on KAYPROs.

    .   Ray's advice was right on the money - I pass his
        advice to the net so that others can benefit.


THE SYMPTOM: The KAYPRO won't work.  The screen may light up and
the "Insert Disk ..." message may appear, but the 'A' Drive
light won't go on and the computer won't boot.


THE PROBLEM: Especially on units older than the '84' series, the
male connector on the power-supply board was not well soldered
to the foil.

    .   Over time, one of the ten connector pins may
        separate electrically from the foil.

    .   The disconnect may be intermittent or
        load-dependent - the presence of all voltages does
        NOT prove that the problem does not exist.


THE FIX: Obvious, but here it is step-by-step.

    .   The power supply board is mounted on the rear panel
        of the unit, below and at right angles to the main
        board.

    .   Remove the cover (ten screws).  Unplug the ten-pin
        connector from the power supply board and note its
        orientation.

    .   Remove the four screws that hold the power supply
        board to the rear panel, slip off the cable loops
        that may be attached to the power supply's plastic
        'legs', and take out the board.  (It helps also to
        remove the diagonal strut that is attached to the
        bottom and rear panels for rigidity.)

    .   Using a small-wattage (15-25w) soldering iron and
        ROSIN core solder, firmly connect each of the ten
        connector pins to the foil (by flowing solder from
        the pin to the foil).

       ..  The printed circuit board is quite sturdy and
           the connections to the board cover a large area.

       ..  Even those who have never soldered a circuit
           board should be able to do this task after
           asking someone with experience for general
           advice on soldering circuit boards.

    .   Reinstall the power supply board and plug in the
        connector (carefully check the connector's
        orientation).


That's it.

                             ###