Memory Troubleshooting - HP 9845B/C CE Handbook

4-10
9845B/C Mainframe Troubleshooting
Memory Troubleshooting
These memory maps and hardware locators show how to interpret memory error messages
obtained from system exerciser and diagnostic memory tests.
Error message decoding:
RWM error example;
MEMORY ERROR BLK BB ADDRESS AAAAA HAS XXXXXX NOT YYYYYY
BB
=
The octal block number, hardware correllation is;
a
=
A28 1
=
A27
2,4, 6, 10, 12, 14, 16 are on A26. 2 is not used.
AAAAA
=
Is the octal address in the range 000040-077777,
If most significant digit is 0-3, address is low.
If most significant digit is 4-7, address is high.
XXXXX
=
Data read from address.
YYYYY
=
Data written into address.
To determine bit that failed, convert octal data to binary.
Example, XXXXXX
=
000400
=
000 000 000 100 000 000
yyyyyy
=
000000
=
000 000 000
~OO
000 000
Failed bit
---------~-
ROM error example:
Count binary bits from the right starting with zero, the failed bit
is 8. Refer to the hardware diagrams for bit/chip location on the
memory board.
ROM CHECKSUM FAILURE BLK BB ADDRESS SSSSSS - EEEEEE
BB
=
Octal block number, the hardware correlation is;
3
=
A28(46)
7,13,
=
A44
5
=
A27
11,15
=
A42
SSSSSS
=
Starting address of the ROM that failed.
EEEEEE
=
Ending address of the failed ROM.