2800 HD (250-3550)          Memory Upgrade              Faxback Doc. # 1843

Memory Chip Kit:   25-3554  (order from Tandy National Parts)

┌─────────────────────────────┐
│Memory Upgrade Installation: │
└─────────────────────────────┘

The 2800 HD comes with 1MB of memory, expandable to 2MB.

A special memory upgrade kit (Cat. no. 25-3554) is available for use in the 
Tandy 2800 HD to expand to 2MB memory. 

To install the memory expansion card:

1. Be sure that the computer is turned off.
2. Disconnect the computer's battery and any peripheral devices.
3. Remove the plate that covers the memory expansion card port. This is the
   lower port on the back of the computer (right side). Save the two screws
   that hold the plate in place.
4. Slide the memory expansion card, component side up, into the memory
   expansion card slot. Guide the memory expansion card so that the card's
   connector fits into the connector in the computer. You might have to
   raise the card slightly to locate the connector.
5. Push the memory expansion card until it clicks into place.
6. Use the two screws removed in Step 3 to fasten the memory expansion card.
7. Reconnect the battery and all peripheral devices.

┌────────────────────────────────────────────────┐
│Designating Extended Memory as Expanded Memory: │
└────────────────────────────────────────────────┘

TEMM_28.SYS, a device driver located on the MS-DOS/DeskMate diskette,
enables MS-DOS to access memory above 640kb.  This driver will support the 
Lotus/Intel/Microsoft EMS 4.0 standard and can be used in the same manner 
as all other expanded memory systems that use this standard.

To Install TEMM_28.SYS:

The TEMM_28.SYS is also located in the c:\dos directory of the hard drive.
Include in the CONFIG.SYS file, the following device command:

     device=c:\dos\temm_28.sys

Upon bootup, the EMS driver tests the available memory:

     Testing EMS Expanded Memory Page
     Number:nnn

The nnn represents the page number currently under test. If the diagnostics 
fail, the following message is displayed:

     Expanded Memory Failed diagnostic test

Turn off the computer, wait about 20 seconds, and turn it on again. If it 
fails again, make sure the:

     1.  config.sys device statement is entered correctly.
     2.  EMS driver is installed on the hard drive.
     3.  Memory board is installed correctly.

(rjs-06/10/93)