saca@ihlpa.UUCP (Saca) (02/13/86)
I have an IBM-PC with 256K at home and I'm getting a bunch of
memory errors. I would like to know where the failing memory
chip(s) is located in the mother-board. After running the
diagnostic program to test the 256K of memory I'm getting the
following error messages:
04F1
045A
0402
0429
I would really appreciate if somebody can tell me what these errors
mean so I can decide whether to try to fix it by myself or take
the computer to an authorized IBM dealer. I would hate to pay a lot
of money for something as simple as replacing a memory chip (if I
know which one(s)).
Fernando Saca
AT&T Bell Laboratories
ihnp4!ihlpa!sacakadie@uiucdcs.CS.UIUC.EDU (02/14/86)
I am sorry I can't be of direct help, but purhaps I can give you a reference. The March 11 (Really Feb. 11) PC magazine has several pages of explaination about memory errors and what do to about them. Carl Kadie U. of Illinois The March 11 (Really Feb. 11) PC Magazienc
manson@utecfc.UUCP (Bob Manson) (02/20/86)
Several months ago, someone asked what a PARITY CHECK 2 error was. I replied directly, but I don't know if the information was ever received (I may not have included a return address). Since someone else has a memory problem, I thought that I would simply post my answer. An item in the User-to User column in the 30 October 1984 issue of PC Magazine gave a description of what a parity check error is and how to identify the chips associated with the error. Basically, a PARITY CHECK 1 error means that you have a problem with the memory on the mother board. PARITY CHECK 2 would indicate a problem with the memory on an expansion card. Along with the PARITY CHECK error message, apparently an address code is also displayed. According to the man who wrote the letter(Wesley K. Merchant), if you can't read the address code, (the error message will, in the case of failure during diagnostics, scroll past fairly rapidly) you should obtain a copy of the IBM advanced diagnostics, enable the error logging and loop on the memory test. (Diagnostic programs are sometimes included when you buy expansion boards). When the memory failure occurs, the address code--in the form XYZZ 201, where 201 would indicate a memory error--can be deciphered using the following table: The "X" portion of the address identivies which 64K bank is failing. 0YZZ = 1ST 64K BANK (0-64K) 5YZZ = 6TH 64K BANK (320-384K) 1YZZ = 2ND 64K BANK (64-128K) 6YZZ = 7TH 64K BANK (384-448K) 2YZZ = 3RD 64K BANK (128-192K) 7YZZ = 8TH 64K BANK (448-512K) 3YZZ = 4TH 64K BANK (192-256K) 8YZZ = 9TH 64K BANK (512-576K) 4YZZ = 5TH 64K BANK (256-320K) 9YZZ = 10TH 64K BANK (576-640K) The "Y" portion of the address is NOT important unless you have the old 16K chips. It will identify the failing 16K bank. X0ZZ = 1ST 16K ROW X8ZZ = 3RD 16K ROW X4ZZ = 2ND 16K ROW XCZZ = 4TH 16K ROW The "ZZ" portion of the error message is the BINARY number of the 64K chip in the indicated 64K bank XY00 = PARITY CHIP XY10 = DATA BIT 4 XY01 = DATA BIT 0 XY20 = DATA BIT 5 XY02 = DATA BIT 1 XY40 = DATA BIT 6 XY04 = DATA BIT 2 XY80 = DATA BIT 7 XY08 = DATA BIT 3 XYAA = EMPTY BANK-CHECK SWITCHES XYFF = EMPTY BANK-CHECK SWITCHES I hope this helps. ----------------------------------------------------------------- Bob Manson University of Toronto Department of Civil Engineering Toronto, Ontario