IBM RT PC 10 Hardware Maintenance And Service page 253

Fixed-Disk Drive Type R40
The Fixed-Disk Drive Type R40 has a storage capacity of at least 40M
bytes of formatted data.
There are no adjustments or individually field-replaceable parts on this
drive.
Specifications
Disk Size
Maximum number
Adapter
Removal and Replacement Procedures
5.25 inch fixed disk
1
Personal Computer AT Fixed-Disk and Diskette
Drive Adapter
Use the "Fixed-Disk Drive Removal" on page 4-28 procedure for removal.
Use the "Fixed-Disk Drive Replacement" on page 4-30 procedure for
replacement.
8-4 Service Manual