IBM 6151 Maintenance And Service Manual page 184

Step 8
The failure may be caused by a device or adapter attached to the
FRU indicated by the SRA number in the SRN. For example, the
SRA number may indicate a tape drive and the tape drive adapter
may be the failing FRU, or the SRA number may indicate the tape
drive adapter and tape drive is the failing FRU.
4. Write the Service Request Number here:
13 - 234-
- - -
AJZB176
DOES THE SRA NUMBER INDICATE A SINGLE-FRU
DEVICE OR AN ADAPTER FOR A SINGLE-FRU DEVICE?
NO Go to "Step 10" on page 3-0060-10.
YES Continue on the next page.
3-0060-8 Service Manual