IBM 6151 Maintenance And Service Manual page 119

98B
Compatibility Problem
This SRA number indicates that there is a compatibility
problem between some of the system components. Look at the
FRU indicated by the next SRA after the 98B. That FRU is
incompatible with some other system component. For more
information, see the IBM 6100 Engineering Change
Announcements (ECAs).
991
Obvious System Unit Problem
Find the correct removal procedure in Section
4;
then
exchange the FRU. Run System Checkout after exchanging
the FRU.
A1x
Fixed-disk and Diskette Drive Cable
Additional Tests: Run the Diskette Drive Checkout.
Removal Procedure: See Adapter Removal in Section 4.
Repair Checkout: Run the Fixed-Disk Drive and Media
Checkout and the Diskette Drive Checkout.
(6/88) Problem Isolation Charts 3-0020-41