DOCUMENT:Q76922  21-NOV-1999  [msdos]
TITLE   :ROM and RAM Error Codes Explained
PRODUCT :Microsoft Disk Operating System
PROD/VER:MS-DOS:5.0
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft MS-DOS operating system version 5.0 
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SUMMARY
=======

In the event that a RAM or ROM chip fails, a multidigit error code will be
displayed. The error code is displayed only briefly, then replaced by the
message

   PARITY CHECK x

where if x=1, the problem is on the system board or is power supply problem, and
if x=2, the problem is on one of the memory expansion adapters.

The multidigit error codes can be used to determine where the chip error
occurred.

MORE INFORMATION
================

ROM Error Codes
---------------

During power-on-self-test (POST), a failed ROM chip will display an error code in
the following format

   xx00 ROM

-or-

   xx000 ROM

where xx is the hexadecimal address of the failed ROM.

Not all problems can be identified by an error code, because some problems will
prevent the computer from booting at all.

The following table shows some of the possible error codes and what they mean:

Error Code    Computer     Location of Faulty ROM
----------    --------     ----------------------

C800 ROM       All         Hard disk drive adapter
CC00 ROM       PC,XT       PC network
IO ROM CC00    XT 286,AT   PC network
F600 ROM       PC          U29
F800 ROM       PC          U30
FA00 ROM       PC          U31
FC00 ROM       PC          U32
Fxxx ROM       PC          System board
ROM Error      all         System board
IO ROM xxxxxx  XT 286, AT  Power related

RAM Error Codes
---------------

When the last three numbers of an error code are 201, it indicates an error in
the RAM area. The numbers preceding 201 are the code that identifies the
specific chip. Error code formats appear as follows:

Computer          Error Code Format
--------   -----------------
PC                xxx 201
XT                xxxxx xx 201
AT and PS/2       xxxxxx xxxx 201

Note: x represents hexadecimal characters.

The first one or two characters indicate the bank or expansion adapter, and the
two to four characters preceding 201 represent the specific chip that failed.

If a chip has failed in one of the first few memory banks, the error code may
disappear very quickly. Ensure that the display is warmed-up sufficiently to
show the error code.

For more information, query on the following words:

   parity error and meaning and message

   parity check and error and description

REFERENCES
==========

"The PC Configuration Handbook," John Woram, pages 259-275, Bantam, 1990

"IBM PC Troubleshooting and Repair Guide," Robert C. Brenner, H.W. Sams &
Co., 1985

Additional query words: 5.00

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS500
Version           : MS-DOS:5.0

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