1800 HD  (250-3502)          Memory Upgrades           Faxback Doc. # 1864

You can expand your computer's 1 MB of memory to 3 MB by installing two 1
MB single inline memory modules (SIMMs).

These memory modules can be ordered from Tandy National Parts.  Order two 
MX-7961, listed under catlog number AX2503504.  When contacting National
Parts, refer to the AX catalog number, not the catalog number for the 
computer.

NOTE:  Be sure to specify "Low-Profile SIMMS" when ordering.  The part can
       sometimes be substituted for a "High-Profile SIMM".  The part will
       work, but you cannot close the lid or replace the cover over the 
       SIMMS.

The computer is equipped with 640KB of conventional memory and 384K or
extended memory. Depending on the requirements of the operating system and
the programs you run, you can use the extended memory as expanded memory
(EMS). To do so, use the Setup180 program to enable Shadow RAM and EMS
memory. Then, install the temm1800.sys device driver. For more details on
use in this Utility refer to your MS-DOS Manual.  For a brief description
of settings for temm1800.sys, refer to Faxback document 9594.

CAUTIONS:  If you choose to expand the computer's memory by installing
           SIMMs, you must install two SIMMs. The computer will not
           function properly if you install only one SIMM.

Use the following procedure to install the SIMMs:

1.  Turn off the computer.

2.  Find the compartment cover on top of computer.

3.  Position the SIMM card so that the card's two modules face you and the
    two holes are at the top.

Top of Computer

┌─────────────\──────────────────────────────────────────────────────────┐
│                                            Math                        │
│                                          Coprocessor    E10 E11 E12    │
│                                           ┌─────────\─────\──┼──/────┐ │
│                                           │┌────┐┌───\┐    o o o     │ │
│                                           ││    ││    │   CTRL/CAPS  │ │
│                                           │└────┘└────┘    Reverse   │ │
│                                           └────\──/──────────────────┘ │
└──────────────────────────────────────────────SIMM Sockets──────────────┘

4.  Install one SIMM card in either slot by tilting the card away from you.
    Then, tilt the card back toward you until it snaps into position.

5.  Install the other SIMM card in the remaining slot, as described in Step
    3.

6.  Replace the cover. Then, turn on the computer.

7.  If you want to use the extended memory as expanded memory, install the
    temm1800.sys Utility EMS device driver. To do so, add the following
    line to your computer's config.sys file, using the MS-DOS EDLIN command
    or some other text editor.

    The statement should read as follows:

         device=c:\dos\temm1800.sys

The following table shows the total amounts of extended RAM, Shadow RAM,
or Expanded memory, depending on the total amount of RAM installed in your
computer. You can specify the device driver's memory size up to the amount
of extended RAM shown in the table.

NOTE: Enabling and disabling the Shadow RAM in the Setup program affects
      the amount of extended RAM you can specify in the device driver.
      Refer to Faxback Doc. # 1865 for more information on this option.

┌───────┬───────────┬─────────┬────────┬──────────┬───────────┐
│ TOTAL │ EXTENDED  │ SHADOW  │ SHADOW │  EMS     │ EMS       │
│ RAM   │ RAM       │ RAM     │ RAM    │  SETTING │ MEMORY    │
│       │           │ SETTING │ SIZE   │          │ AVAILABLE │
╞═══════╪═══════════╪═════════╪════════╪══════════╪═══════════╡
│ 1 MB  │ 384 KB    │ Disabled│   0    │  ------- │ 0         │
│       │           │         │        │          │           │
│ 1 MB  │ 0         │ Enabled │   96 KB│  ------- │ 288 KB    │
│       │           │         │        │          │           │
│ 3 MB  │ 2048 KB   │ Enabled │   96 KB│  Disabled│ 288 KB    │
│       │           │         │        │          │           │
│ 3 MB  │ 0 KB      │ Enabled │   96 KB│  Enabled │ 2336 KB   │
└───────┴───────────┴─────────┴────────┴──────────┴───────────┘

NOTE: Extended and expanded RAM are simply two different ways you can
      configure the extra memory (above 1 MB) in your computer. The one
      you choose depends mostly on what programs you use. Some programs
      require one specifically; some programs can use either. Consult your
      software documentation for more information.


(smm/all-08/24/95)