AST RESEARCH, INC.         TECHNICAL BULLETIN #0885               01-17-94




              MEMORY ERRORS WHILE USING TEXAS INSTRUMENT SIMMS


PROBLEM:       When running the AST Advanced Diagnostics program,
               intermittent memory failures occur while executing the
               "Walking Zeroes and Ones" test of the memory diagnostics
               module.

               Also, while running under IBM OS/2 2.1, loading an application
               in a "WIN OS/2" window causes a "General Protection Fault",
               which hangs the system.

CAUSE:         Defective SIMM modules from Texas Instruments. The problem has
               been identified as a design defect within the Revision C die
               of TI's TMS44400 DRAM chip.  The SIMM has a TI part number
               TM124MBK36R-7.  The AST part number is 104000-191

AFFECTED
SYSTEMS:       Any system with Texas Instrument SIMMS identified as Revision
               C installed. The revision number can be identified by
               observing the part number on any of the memory IC's on the
               SIMM module.  The third line of the part number consists of
               three letters, e.g. "TCP". The middle letter of the sequence
               is the revision of the individual IC.  In this example the
               revision is C, which indicates a defective SIMM.

SOLUTION:      Replace the defective revisions of the SIMMS with a known good
               revision - either revision B or a revision above C.