IBM 6151 Maintenance And Service Manual page 442

Fixed-Disk Drive Replacement
Follow the Handling a Fixed-Disk Drive procedures. If needed, see
Section 8.
1. Be sure the terminator resistor and the drive selection jumper
are properly installed. If needed, refer to Section 8.
2. Slide the fixed-disk drive part way into the system unit.
AJZBF026
4-32 Service Manual