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Document:	MS7AA-FA Memory Module Service Guide
Order Number:	EK-MS7AA-SV
Revision:	A01
Pages:	11
Original Filename:

OCR Text

MS7AA-FA Memory Module Service Guide
Order Number: EK–MS7AA–SV .A01

These instructions describe the procedure for identifying and replacing a failing SIMM on the
VAX 7000/10000 or DEC 7000/10000 MS7AA-FA 2-gigabyte memory module.

Digital Equipment Corporation
Maynard, Massachusetts

The MS7AA-FA memory module is the 2-gigabyte memory module for VAX 7000/10000 and
DEC 7000/10000 systems. It is populated with 36 64-Mbyte single in-line memory modules
(SIMMs). Should a SIMM fail it can be replaced in the field.
These instructions tell how to identify the failing SIMM and how to replace a SIMM.
•

Section 1 tells how to identify the failing SIMM from the operating system error log.

•

Section 2 tells how to replace the SIMM.

•

Section 3 tells how to identify the SIMM from the console level. This information may
be needed if the operating system cannot be booted.
NOTE
The part number for the 64-Mbyte SIMM is 54-21718-01. This SIMM can only be used
on a 2-Gbyte module.

1 How to Identify a Failing SIMM from an Operating System Error Log
First you must identify the failing SIMM.
1.

From the error log, locate the error syndrome (for OpenVMS, see Example 1).

Determine if the string is odd or even; is it string 1, 3, 5, or 7, or string 0, 2, 4, or 6?

Determine if the memory interface controller (MIC) error is a MIC A or a MIC B error.

Find the SIMM number in the matrix of Table 1.

For example, from the OpenVMS AXP error log in Example 1, you see:
•

The MS7AA-FA module has an error syndrome 34 (see

•

The failing string is 3, which is odd (see

•

The MIC is B (see

Therefore, from Table 1 you find 34 in the first column, labeled Syndrome. The string, 3, is
odd so you look at the columns labeled Odd. The number under MIC B is J31, the socket
that holds the failing SIMM.
NOTE
The OSF/1 operating system error log will appear in the next version of this document.

Example 1: Sample OpenVMS System Error Report
V M S

SYSTEM ERROR REPORT

******************************* ENTRY
ERROR SEQUENCE 630.
DATE/TIME 21-JAN-1994 10:27:26.26
SYSTEM UPTIME: 0 DAYS 16:29:20
SCS NODE: SUVB02

COMPILED 24-JAN-1994 08:28:00
PAGE 23.
84. *******************************
LOGGED ON: CPU_TYPE 00000002
SYS_TYPE 00000003
VMS V1.5

HW_MODEL: 00000402 Hardware Model = 1026.
MEMORY ERROR KN7AA DEC 7000 MODEL 620
CRD FLAGS
0000
LOG REASON
0004
RELATED ENTRY 1 OF 1
BAD PAGES
00000000
MEMDSC SIZE
00000020
MEMDSC OFFSET
00000060
NUM OF FPRINTS 00000001
FPRINT SIZE
00000050
FPRINT OFFSET
00000080
MEMORY DESCRIPTOR #1
NODE
00000006
LDEV
00004000
MCR
0000000C
AMR
00000343
MEMORY DESCRIPTOR #2
NODE
00000007
LDEV
00004000
MCR
0000000C
AMR
0000034B
1 FOOTPRINTS IN THIS PACKET
CRD FOOTPRINT #1
FOOTPRINT

0004000D
00000006

Syndrome = 34(X)
Bit in Error = 6.
Failing string = 3.
MICB error
Failing node = 6.
SYSTEM TIME
20-JAN-1994 20:18:02.93
LOW ADDRESS
00000000 0153AE00
HIGH ADDRESS
00000000 115E2600
CUM ADDRESS
00000000 100DF800
SCRUB BLOCKSIZE 00000040
STATIC FLAGS
0001
LOG REASON
0008
CALLER FLAGS
00000000
SCRUB FAIL
00000000
MATCH COUNT
0000000E
SCRUB COUNT
0000000E
LAST SCRUB TIME
21-JAN-1994 08:50:02.93

Table 1: 2-Gigabyte SIMM Isolation Matrix
String:

Even

Odd

MIC

String:

MIC

Even

Odd

MIC

Syndrome

J10

J34

J11

J35

J22

J36

J23

J37

J10

J34

J11

J35

J22

J36

J23

J37

J28

J29

J20

J36

J21

J37

J28

J29

J24

J25

J18

J19

J18

J36

J19

J37

J20

J21

J22

J30

J23

J31

J20

J21

J24

J25

J10

J14

J11

J15

J14

J26

J15

J27

J22

J23

J18

J32

J19

J33

J14

J26

J15

J27

J16

J17

J10

J22

J11

J23

J20

J21

J12

J18

J13

J19

J14

J32

J15

J33

J20

J36

J21

J37

J10

J36

J11

J37

J26

J27

J10

J26

J11

J27

J12

J26

J13

J27

J16

J17

J22

J23

J24

J32

J25

J33

J18

J34

J19

J35

J14

J34

J15

J35

J28

J29

J12

J14

J13

J15

J10

J28

J11

J29

J18

J19

J28

J29

J20

J32

J21

J33

J30

J31

J26

J27

J32

J33

J10

J26

J11

J27

J12

J30

J13

J31

J24

J25

J12

J36

J13

J37

J20

J21

J30

J31

J30

J31

J18

J34

J19

J35

J30

J31

J20

J32

J21

J33

J12

J30

J13

J31

J18

J34

J19

J35

J28

J29

J16

J28

J17

J29

J14

J30

J15

J31

J16

J28

J17

J29

J24

J25

J22

J23

J24

J25

J24

J34

J25

J35

J16

J36

J17

J37

J16

J17

J26

J27

J16

J32

J17

J33

J32

J33

J22

J34

J23

J35

J24

J25

J12

J14

J13

J15

J12

J16

J13

J17

2 How to Replace a SIMM
After you have determined the failing SIMM on the memory module, remove the module
from the system and follow this procedure.
CAUTION
You must wear an antistatic wrist strap attached to the cabinet when you handle
any modules.

Remove the cover that shields side 1 of the module by removing the eight small Phillips
screws.

Determine the location of the failing SIMM from Figure 1.

Locate the row of SIMMs on the module that holds the failing SIMM.

Figure 1: SIMM J Connector Numbers

J37
J36
J34
J32
J30
J28
J26

J35
J33
J31
J29
J27

J25
J24
J22
J20
J18
J16
J14

J23
J21
J19
J17
J15

J13
J12
J10
J8
J6
J4

J11
J9
J7
J5
J3

BXB-0687-94

Beginning with the SIMM closest to the gate arrays, remove each SIMM up to and
including the failing SIMM. To remove a SIMM, release the latches on both ends of the
SIMM connector. Insert a #1 Phillips screwdriver as shown in Figure 2, and rotate the
screwdriver until the latch releases. Open both latches. Then turn the SIMM at a 45
degree angle toward the gate arrays and pull the card out of the connector.

Put the failing SIMM aside for return to the appropriate repair facility.

Insert a new SIMM in place of the failing SIMM, angling it into the connector at 45
degrees. Turn it to a vertical position until the latches snap into place. The connector
is keyed in the center so that the correct side of the SIMM faces front.

Insert the other SIMMs back into their connectors.

Replace the module cover.

Figure 2: Removing a SIMM

Side View
BXB-0699A-94

3 How to Identify a Failing SIMM at Console Level on a DEC 7000/10000
While in console mode, you can determine which SIMM has failed. Example 2 shows a
sample console session with the steps to take to identify a failing SIMM.
Example 2: Sample Console Display
>>> set mode diag
>>> set d_startup on
d_startup set to on
>>> show mem
Set
--A

Node
---1

Size
---2048Mb

Base Addr
--------000000000

Intlv
----2-Way

Position
-------0

# 2048MB = 2GB = 8000 0000 (hex)

>>> mem_ex -t 1 -sa 1000000 -ea

7fffffc0
# 8000 0000 - 40 = 7FFF FFC0

ID Program
Device
Pass Hard/Soft Test
Time
-------- -------- --------------- -------- --------- ---- -------49
mem_ex
mem
0
0
0
20:59:54
CPU 0
unexpected exception/interrupt through vector 00000066
process mem_ex, pcb = 007F0620
pc: 00000000 000D6B40
r2: 00000000 0013F8A0
r3: 00000000 001ECCA0
r4: 00000000 00000020

ps: 30000000 00000004
r5: 00000000 00001F04
r6: 00000000 1FBFFFF0
r7: FFFFFFFF FFFFFFFF

[listing of GPRs and FPRs]
Machine Check Logout - base: 00006000
flags:
offsets:
pt0:

00000000 00000000
000001A0 00000110
00000001 00000100

byte_count:
das_debug:
pt1:

80000000 000001D8
00E00555 00000020
00000000 000000FC

[listing of registers]
lbesr2:
lbecr0:

00000000 0000007F
00000000 03000500

lbesr3:
lbecr1:

00000000 0000007F
00000000 000C8040

# 03000500 x 20 (hex) = 6 000A000
lmmr0:

00000000 00000000

lmmr1:

00000000 00000321

[more registers]
ms7aa0_lber:00000000 00040203
ms7aa0_lbecr1:00000000 000C8040
ms7aa0_msynda:00000000 000000F3
ms7aa0_msyndb:00000000 000000F3
Failing FRU: ms7aa0
>>> CPU:0 Halt Code = 1
operator initiated halt
PC = 13ee0c

ms7aa0_lbecr0: 00000000 03000500
ms7aa0_mera:
00000000 00000C07
ms7aa0_merb:
00000000 00000007

>>> dep -l ms7aa0:21c0 10000002

>>> mem_ex -t 1 -f -sa 60000000 -l 2000000

Example 2 (continued on next page)
7

Example 2 (Cont.): Sample Console Display
ID Program
Device
Pass Hard/Soft Test
Time
-------- -------- --------------- -------- --------- ---- -------4f
mem_ex
mem
0
0
0
21:01:29
>>> dep -l ms7aa0:21c0 10000000

>>> dep -l ms7aa0:2140 ff
>>> dep -l ms7aa0:2440 ff
>>> mem_ex -t 1 -f -sa 60000000 -l 2000000

ID Program
Device
Pass Hard/Soft Test
Time
-------- -------- --------------- -------- --------- ---- -------51
mem_ex
mem
0
0
0
21:01:31
>>> ex -l ms7aa0:2140
ms7aa0: 00002140 00000015
>>> ex -l ms7aa0:2180
ms7aa0: 00002180 00000045
>>> ex -l ms7aa0:4180
ms7aa0: 00004180 000000F3
>>> ex -l ms7aa0:2100
ms7aa0: 00002100 03000500
>>>

# Address of MERA register

# Address of MYSNDA register
# Address of MYSNDB register

# Address of FADR register

Enter diagnostic mode.
Determine the size of physical memory using the show memory command.

Subtract 40 from the highest memory address to determine the ending address for
mem_ex.

Run mem_ex test 1 from 16 meg (100 0000) to the top of memory.
Multiply the contents of the LBERC0 register by 20 (hex) to get the failing address.

Determine the failing memory module, ms7aa0.

Disable ECC checking on the failing module.

Initialize all of memory on the failing module by running mem_ex test 1 with the
-f option on the 32 meg address block that contains the failing address. This will clear
the double-bit errors that were generated during memory self-test.

Starting address = 30 0500 X 20 = 6000 A000 = failing byte address
^ from callout 
Test address = 6000 0000
Length = 20 0000
Enable ECC checking on the memory module by depositing 1000 0000 into Memory
Diagnostic Register A.

Clear the error registers on the memory module.

Run mem_ex test 1 with the -f option on the 32 meg address block that contains the
failing address.

Examine Memory Error Register A on the failing memory module to determine the
failing syndrome (see Figure 3).

Examine Memory Error Syndrome Registers A and B to determine the failing bank.

The contents of Memory Error Syndrome Register A gives the error syndrome.

Examine the Failing Address Register (FADR) on the failing module. Use Table 2 to
determine if the failing string is Odd or Even.

The contents of FADR indicates the string.

From this information you can identify the failing SIMM.
For example, from the console display in Example 2, you see:
•

The MS7AA-FA module has an error syndrome 45 (see  ).

•

The string is even (see  ). From the show mem command (see ) we know the interleave is 2-way. Using the contents of FADR  and Table 2 we know the string is
even.

•

The MIC is A (see  ) because CERA is set in MERA (see  and Figure 3).

Therefore, from Table 1 you find 45 in the first column, labeled Syndrome. The failing string
is even so you look at the columns labeled Even. The number under MIC A is J2, the socket
that holds the failing SIMM.
Table 2: Using FADR Bit to Determine Odd/Even String
No. of
2-Gbyte
Modules

Interleave
Count

FADR Bit
bit 1 (0 = Even string 1 = Odd string)

bit 2 (0 = Even string 1 = Odd string)

bit 3 (0 = Even string 1 = Odd string)

The interleave count for one 2-Gbyte module with four 512-Mbyte modules is 4. Use FADR bit 2 in this case.

Figure 3: Memory Error Register A
31

12 11 10

RSVD
UCERB: Uncorrectable Error on MIC-B
UCERA: Uncorrectable Error on MIC-A
BNKER: Bank Conflict Error
FSTR: Failing String
CERB: Correctable ECC Error on MIC-B
CERA: Correctable ECC Error on MIC-A
APER:Address Parity Error
MULE: Multiple Errors
UCER: Uncorrectable Read Error
CER: Correctable Read Error
BXB-0219A-93

NOTE
For more information about the memory registers, see the MS7AA Memory Technical
Manual.