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    AST RESEARCH, INC.        TECHNICAL BULLETIN # 1164                  5-3-95

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    			  MANHATTAN P OR V TOSHIBA DRAM COMPATIBILITY

    PROBLEM

    One type of Toshiba TC5117400 DRAM is incompatible with the memory paging
    feature introduced in BIOS release 1.09.

    ERROR SYMPTOMS

    AST has confirmed the DRAM can cause the following errors:

    The computer hangs or freezes without an error code.

    The computer reports a parity error has occurred.

    The computer reports a  "Unexpected Non-Maskable Interrupt" error has
    occurred.

    The computer reports  "NVRAM BAD".

    SYSTEMS AFFECTED
    AST PART NUMBER AND DESCRIPTION

    501500-XXX     MANHATTAN V5090
    501502-XXX     MANHATTAN P5090

    SOLUTION

    Use TOSHIBA DRAMs that are compatible with the memory paging feature
    introduced in BIOS version 1.09.

    IDENTIFYING THE INCOMPATIBLE TOSHIBA TC5117400 DRAMs

    Inspect the DRAMs on the SIMM.  The incompatible DRAM has one of the following
    Toshiba part numbers marked on top of the chip:

    TC5117400J-XX
    TC5117400SJ-XX
    (where XX is either 60 or 70, indicating DRAM access time in nanoseconds)

    IDENTIFYING THE COMPATIBLE TOSHIBA TC5117400 DRAMs

    Toshiba is now producing revision B of the TC5117400 DRAM.  Revision B is
    100% compatible and does not cause problems. To verify the DRAM is compatible,
    inspect the part number that is located on the top of the DRAM chip for the
    letter "B".  For example, the following part numbers are acceptable:

    TC5117400BJ-XX.
    TC5117400BSJ-XX

    ADDITIONAL INFORMATION

    Any SIMM manufacturer may have used the incompatible TOSHIBA DRAM when they
    manufactured their SIMM module.  SIMM modules consist of small silicon chips
    that are soldered onto a small Printed Circuit Board (PCB).  Most of the small
    silicon chips are called DRAMs (Dynamic Random Access Memory).  When SIMM
    modules are manufactured, several different DRAM manufacturers can be
    installed on the PCB.  This Technical Bulletin discusses only the DRAM that
    is soldered on the SIMM module.

    Please review Software Bulletin # 0178C for additional information regarding
    BIOS release 1.09.