AST RESEARCH, INC.         TECHNICAL BULLETIN #0875              10-15-93




                     DESKTOP SYSTEMS POWER SUPPLY ISSUES


PROBLEM:       Certain desktop systems experience intermittent hangs during
               power up. The symptoms are: the display is corrupt with a
               white or blue screen, or random characters appear. Also, some
               systems may experience intermittent failure of the floppy
               drive.  These floppy drive errors occur randomly.

CAUSE:         The cause of these symptoms are power supplies manufactured by
               Delta.  These supplies contain a defective component which
               causes ripple voltage on the five volt line, which disrupts
               the operation of the system in the manner described above.

AFFECTED
SYSTEMS:       The following systems should be checked for the correct
               revision level of power supply if they exhibit the above
               symptoms and their serial numbers are below the numbers listed
               below.

          AST                            SYSTEM SERIAL
      PART NUMBER    DESCRIPTION         NUMBER IS BELOW
      
      501126-XXX     Premmia             USD 6001026
      501127-XXX     Premmia             USD 7001087
      501128-XXX     Premmia             USD 8001032
      501129-XXX     Premmia             USD 9001059
      501204-XXX     Premmia             MTUSR7001141
      501278-XXX     Bravo               MTUSB1001459
      501220-XXX     Advantage Plus      USW2006274
      501221-XXX     Advantage Plus      USW3022105

SOLUTION:      The system should be serviced as described in AST Technical
               Document FCN #0097.