IBM 6151 Maintenance And Service Manual page 244

Step 5
The letter of the 37x SRA identifies the failing module within a
horizontal row of modules. The horizontal row is determined by
the switch bank setting that corresponds to the letter in the 21x
SRA.
1. Find the switch bank that corresponds to the letter in the 21x
SRA.
2. Find the module within the same horizontal row that
corresponds to the letter in the 37x SRA.
3. Exchange the module.
4. Run xxK Bytes of IBM AT Memory Checkout. If needed see
page 2-17.
ABC DEFGHIJKLMNOPQR
o 00000000000000000
~O
00I
0
o 00000000000000000
DO
00I
o 0000
~
0
~ ~
0000
~
DO DO
0
,\,JZB1~:J
DID A FAILURE OCCUR WITH THE SAME SRN?
YES Exchange the IBM AT 512 KB Memory Expansion Option;
then go to "Step
7"
on page 3-2100-8.
NO Go to "Step 7" on page 3-2100-8.
3-2100-6
Service Manual