3200  (250-1633)      Upgrading the Microprocessor    Faxback Doc. # 2835

The system board has a socket in which you can install an upgrade
microprocessor, to increase the processing power and speed of your
computer.  You can purchase any of several upgrades through your local
Radio Shack store.

To upgrade the microprocessor:

1.  Turn the computer off, unplug the power cord, disconnect all
    peripheral devices, and remove the computer-chassis cover.

2.  Locate the microprocessor upgrade socket on the system board.

3.  If no microprocessor is installed in the upgrade socket, proceed to
Step 4.  If a microprocessor is already installed in the upgrade socket,
pull it from the socket.  Use the chip puller tool included in the Intel
upgrade kit.  Remove the microprocessor carefully to avoid damaging its
pins.  Be sure to pull on the microprocessor itself, not the socket.

4.  Install the upgrade microprocessor.

a.  Align the microprocessor with the socket.  Match pin 1 of the
    microprocessor (indicated by a dot or beveled corner) with the
    beveled corner marking etched on the system board.

b.  Carefully insert the microprocessor into the socket.  Do not bend any
    of the pins during insertion.  Push down on the microprocessor until
    it is fully seated in the socket.

5.  Set the jumpers on the system board (Table 3) according to the type
    of microprocessor that you installed in the upgrade socket.  The
    jumper numbers (for example, E6) are printed on the system board.  In
    Table 3, On means that the jumper has two pins and both are covered
    by a jumper block.  Off means that the jumper block is removed from
    all jumper pins, or that the jumper block is on 1 pin of a 2-pin
    jumper.  Pins 1 & 2 means that the jumper block covers the first two
    pins of a three-pin jumper; Pins 2 & 3 means that a jumper block
    covers the second two pins of a three pin jumper.

────────────────────────────────────────────────────────
TABLE 3 SYSTEM BOARD JUMPER SETTINGS-MICROPROCESSOR TYPE
────────────────────────────────────────────────────────
MICROPROCESSOR              JUMPER NUMBER
TYPE                E6     E7     E8     E9     E10
────────────────────────────────────────────────────────
80487SX             Pins   Pins   Pins   Pins   Pins
                    1&2    1&2    2&3    1&2    2&3

80486SX             Pins   Pins   Pins   Pins   Pins - Default Settings.
                    1&2    1&2    1&2    2&3    2&3

80486DX             Pins   Pins   Pins   Pins   Pins
                    1&2    1&2    1&2    2&3    2&3

80486DX2            Pins   Pins   Pins   Pins   Pins
                    1&2    1&2    1&2    2&3    2&3

OverDrive           Pins   Pins   Pins   Pins   Pins
                    1&2    1&2    2&3    1&2    2&3

Pentium             Pins   Pins   Pins   Pins   Pins
OverDrive*          2&3    1&2    2&3    1&2    2&3
─────────────────────────────────────────────────────────────
This system uses only 5-volt OverDrive and Pentium OverDrive
microprocessors.
─────────────────────────────────────────────────────────────

6.  Set the microprocessor clock speed jumper according to the external
    clock speed of the microprocessor you installed (Table 4).

TABLE 4.  SYSTEM BOARD JUMPER SETTINGS - CLOCK SPEED
──────────────────────────────
MICROPROCESSOR
SPEED                 E2
──────────────────────────────
25/50 MHz             Pins 1&2
33/66 MHz             Off
──────────────────────────────

7.  Replace the computer chassis cover.  Reconnect peripheral devices and
    plug in the power cord.  Turn on the system.

(SMC-05/24/94)