40 MB Internal Hard Drive (250-4057)     Settings      Faxback Doc. # 5073

* The 40 MB Hard Disk Drive is a half-height Winchester fixed-disk drive.

* The 40 MB Hard Disk Drive interface is compatible with the Seagate
  ST506/ST412 standard interface.

* Can operate at temperatures from 50 to 122`F with 8 to 80% non-condensing
  humidity.

* The standard Drive Select setting set at the factory configures the 40 MB
  Hard Disk Drive as the first (primary) disk drive.  The standard
  Terminator setting configures the Hard Disk Drive as the terminal disk
  drive.

SEAGATE ST 251  POSSIBLE PIN/SWITCH SETTINGS

Starting from the left, the first four pairs of pins are for drive
selection.  Jumper one of these sets to configure the hard disk as Drive
1,2,3, or 4 (C,D,E, or F), respectively.

NOTE: The third and fourth sets of pins provide hardware support for a
third and fourth hard disk.  The Hard Disk Controller board (25-4060) for
your computer does not support more than two hard disk drives.

The last three pairs of pins are not used.

This drive includes a resistor for drive termination.  Be sure the resistor
is installed to configure the hard disk as the terminal drive.  Otherwise,
remove the resistor with tweezers or needle-nosed pliers.

Drive Select / Termination Information
Seagate ST-251

                                 ┌─────────┐
                                 └─────────┘<------>Termination
      │                                                      │
      │Power       34 Pin         Jumper pin       20 Pin    │
      │Connector   Connector      1 - 16           Connector │
      │        ┌──┐1 ││          ┌─────────────────┐1 ││     │
      └────────┘  └──┘└──────────┘ : : : : : : : : └──┘└─────┘
                                  16              02
                                  15              01

                  16  14  12  10  08  06  04  02
                  15  13  11  09  07  05  03  01
                  │   │   │   │   │   │   │   │
         Radial───┘   │   │   │   │   │   │   └───Drive Select 1
                      │   │   │   │   │   │
         Reserved─────┘   │   │   │   │   └─────Drive Select 2
                          │   │   │   │
         Write Fault──────┘   │   │   └─────Drive Select 3
                              │   │
               Life Test──────┘   └─────Drive Select 4



(smm 08/26/93)