40 MB Internal Hard Drive (250-4061)      Addendum     Faxback Doc. # 4972

1. Please use the following chart for the MIC Model HH 1050 drive instead
   of the one on page 6 of the Installation manual.

MIC MODEL HH 1050

PRIMARY DRIVE:

Set Switch 1 to ON (down).
Set the Terminator Switches
(5-10) to ON for a two-HD
system.  All other switches
should be OFF (up).

SECONDARY DRIVE:

Set Switch 2 to ON (down).
Set the Terminator Switches
(5-10) to ON.  All other
switches should be OFF (up).

2. Please use the following illustration instead of the one on page 8 of
   the Installation Manual.

 1   2   3   4   5   6   7   8   9  10
┌─┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐
│ │ ├┴┤ ├┴┤ ├┴┤ │ │ │ │ │ │ │ │ │ │ │ │ Primary Hard Disk (Terminal)
├┬┤ │ │ │ │ │ │ ├┬┤ ├┬┤ ├┬┤ ├┬┤ ├┬┤ ├┬┤
└┴┘ └─┘ └─┘ └─┘ └┴┘ └┴┘ └┴┘ └┴┘ └┴┘ └┴┘



 1   2   3   4   5   6   7   8   9  10
┌─┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐ ┌┬┐
│ │ ├┴┤ ├┴┤ ├┴┤ ├┴┤ ├┴┤ ├┴┤ ├┴┤ ├┴┤ ├┴┤ Primary Hard Disk (Non-Terminal)
├┬┤ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │
└┴┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘ └─┘


 1   2   3   4   5   6   7   8   9  10
┌┬┐ ┌─┐ ┌┬┐ ┌┬┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐ ┌─┐
├┴┤ │ │ ├┴┤ ├┴┤ │ │ │ │ │ │ │ │ │ │ │ │ Secondary Hard Disk (Terminal)
│ │ ├┬┤ │ │ │ │ ├┬┤ ├┬┤ ├┬┤ ├┬┤ ├┬┤ ├┬┤
└─┘ └┴┘ └─┘ └─┘ └┴┘ └┴┘ └┴┘ └┴┘ └┴┘ └┴┘

MIC Model HH 1050 Drive Select and Terminator Switch Settings.

3. Please use the following chart instead of the one on page 28 of the
   installation manual.

──────────────────────────────────────┬────────────────────────────────────
CONTROL DATA                          │MICROSCIENCE
MODEL 94205-51                        │MODEL HH 1050
──────────────────────────────────────┼────────────────────────────────────
Starting from the left, the first four│Switches 1-4 are for drive selection
pairs of pins are for drive selection.│Set one of these switches in the ON
Jumper one of these sets to configure │position to configure the hard disk
the hard disk as Drive 1,2,3,or 4 (C,D│as Drive 1,2,3,or 4 (C,D,E,or F),
E, or F), respectively.               │respectively.
                                      │
NOTE: The third and fourth sets       │NOTE: Switches 3 and 4 provide
of pins provide hardware              │hardware support for a third and
support for a third and fourth        │fourth hard disk.  The Hard Disk
hard disk.  The Hard Disk             │Controller board (25-4060) for your
Controller board (25-4060)            │computer does not support more than
for your computer does not            │two hard disk drives.
support more than two hard            │
disk drives.                          │Switches 5-10 are for drive
                                      │termination.  Set all these switches
The last three pairs of pins are not  │in the ON position to configure the
used.                                 │hard disk drive as the terminal
                                      │drive.  Otherwise, set ALL these
This drive includes a resistor for    │switches in the OFF position.
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.      │
                                      │
NOTE: Re-installing the terminator    │
resistor requires partial disassembly │
of the hard disk drive.  Never attempt│
to disassemble the hard disk drive.   │
Servicing the hard disk drive requires│
special facilities.  Take the drive to│
a authorized Radio Shack Service      │
Center for servicing.                 │
──────────────────────────────────────┴────────────────────────────────────

(css/BKL-01/10/96)