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From: chapman@acf4.UUCP (Gary W. Chapman)
Newsgroups: comp.sys.ibm.pc
Subject: Re: PC Memory error
Message-ID: <12550006@acf4.UUCP>
Date: Thu, 21-May-87 16:50:00 EDT
Article-I.D.: acf4.12550006
Posted: Thu May 21 16:50:00 1987
Date-Received: Sat, 23-May-87 12:39:46 EDT
References: <19318@sun.uucp>
Organization: New York University
Lines: 26

There is a nice book entitled "IBM PC Troubleshooting & Repair Guide" by
Robert C. Brenner from SAMS publishers, which provides a lot of useful
troubleshooting information for PCs.  The following chart is provided for
diagnosing memory chip failures:

             xx               xx               201

  System Board Memory     Failed Chip
        (Bank xx)

       00 = Bank 0          00 = Parity
       04 = Bank 1          01 = D0 chip
       08 = Bank 2          02 = D1 chip
       0C = Bank 3          04 = D2 chip
                            08 = D3 chip
                            10 = D4 chip
                            20 = D5 chip
                            40 = D6 chip
                            80 = D7 chip

Thus for error message 04 80, the chip is in bank 1, chip D7.

My XT has the banks labeled, with bank 0 closest to the rear of the machine;
the parity chip is the leftmost chip in each bank. 

          -- Gary Chapman (chapman@nyu-acf1.arpa)