ROM and RAM Error Codes Explained

This article was previously published under Q76922
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SUMMARY
In the event that a RAM or ROM chip fails, a multidigit error codewill be displayed. The error code is displayed only briefly, thenreplaced by the message
PARITY CHECK x
where if x=1, the problem is on the system board or is power supplyproblem, and if x=2, the problem is on one of the memory expansionadapters.

The multidigit error codes can be used to determine where the chiperror occurred.
MORE INFORMATION

ROM Error Codes

During power-on-self-test (POST), a failed ROM chip willdisplay 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 someproblems will prevent the computer from booting at all.

The following table shows some of the possible error codesand what they mean:
Error Code    Computer     Location of Faulty ROM----------    --------     ----------------------C800 ROM       All         Hard disk drive adapterCC00 ROM       PC,XT       PC networkIO ROM CC00    XT 286,AT   PC networkF600 ROM       PC          U29F800 ROM       PC          U30FA00 ROM       PC          U31FC00 ROM       PC          U32Fxxx ROM       PC          System boardROM Error      all         System boardIO ROM xxxxxx  XT 286, AT  Power related				

RAM Error Codes

When the last three numbers of an error code are 201, it indicates anerror in the RAM area. The numbers preceding 201 are the code thatidentifies the specific chip. Error code formats appear as follows:
Computer          Error Code Format--------   -----------------PC                xxx 201XT                xxxxx xx 201AT and PS/2       xxxxxx xxxx 201				
Note: x represents hexadecimal characters.

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

If a chip has failed in one of the first few memory banks, the errorcode may disappear very quickly. Ensure that the display is warmed-upsufficiently 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
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Article ID: 76922 - Last Review: 12/04/2015 09:10:07 - Revision: 1.0

Microsoft MS-DOS 5.0 Standard Edition

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