MMPC Model 10/20  (250-1640/41)       Settings         Faxback Doc. # 6110

The following table shows the settings for jumpers on the main logic
board.  A hyphen between pin numbers indicates that a jumper should be
installed to connect those two pins.  For example, "1-2" indicates that
the jumper should be installed on Pins 1 and 2.  An asterisk (*)
indicates the default (factory) setting.

   Note:  Before changing the jumper settings for W1 through W5, open the
          computer and remove the drive tray.

Caution:  Incorrect jumper settings can cause a malfunction or a decrease
          in performance.

┌──────────────┬───────┬─────────────┬──────────────────────────────┐
│Function      │Jumpers│ Settings    │Options                       │
├──────────────┼───────┼─────────────┼──────────────────────────────│
│Clock Speed(1)│ W1    │ 1-2*        │ 25/50/75  MHz                │
│              │       │ Parked      │ 33/66/100 MHz                │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│Power         │ W2    │ 1-2         │ Indicator lights when        │
│Indicator/    │       │             │  power is on and flashes     │
│Hard Drive    │       │             │  when hard drive activity    │
│              │       │             │  occurs                      │
│              │       │ Parked*     │ Indicator lights only        │
│              │       │             │  when power is on            │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│Serial Port   │ W3    │ 1-2*        │ COM1 or COM3 selected;       │
│Interrupts    │       │             │  IRQ4 enabled                │
│              │       │ 2-3         │ COM3 selected; IRQ11         │
│              │       │             │  enabled                     │
│              │       │ Parked      │ Port Disabled                │
│              │ W4    │ 1-2*        │ COM2 or COM4 selected;       │
│              │       │             │  IRQ3 enabled                │
│              │       │ 2-3         │ COM4 selected; IRQ10         │
│              │       │             │  enabled                     │
│              │       │ Parked      │ Port Disabled                │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│Parallel Port │ W5    │ 1-2*        │ IRQ7 enabled                 │
│Interrupts    │       │             │                              │
│              │       │ 2-3         │ IRQ5 enabled                 │
│              │       │ Parked      │ No Parallel port             │
│              │       │             │  interrupt                   │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│Upgrade       │ W6    │ 1-2         │ i486 DX, i487 SX, i486 DX2   │
│Processor     │       │             │ ODPR, and i486 DX4 ODPR      │
│Support (1)   │       │             │ supported.                   │
│              │       │ 2-3*        │ i486 SX, i486 DX2 ODP, and   │
│              │       │             │ i486 DX4 ODP supported.      │
│(Please see   │ W7    │ 1-2         │ Processor in upgrade socket  │
│ NOTE below)  │       │             │ supported.                   │
│              │       │ 2-3*        │ Original Surface-Mount       │
│              │       │             │ processor supported.         │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│On-Board      │W8     │ 1-2         │ Disable on-board video       │
│Video Enable  │       │             │                              │
│              │       │ 2-3*        │ Enable on-board video        │
├──────────────┼───────┼─────────────┼──────────────────────────────┤
│On-Board      │W9     │ 1-2         │ Enable on-board video        │
│Video         │       │             │  interrupt                   │
│Interrupt     │       │ Parked*     │ Disable on-board video       │
│              │       │             │  interrupt                   │
├──────────────┴───────┴─────────────┴──────────────────────────────┤
│*Indicates the default setting.                                    │
└───────────────────────────────────────────────────────────────────┘

(1)  Model-specific documentation may contain specific
     information on these jumpers.

Caution:  The Clock Speed jumper is set at the factory to match your
          processor speed.  Change the jumper setting only if you have
          installed an upgrade processor.  See "Installing an Upgrade
          Processor."

NOTE:  Microprocessor Bulletin for PGA Version of main logic board.***

       The W7 Upgrade Processor Support pin is not required for operation
       with the PGA version of the i486 SX.  The W7 pin has been removed
       from the main logic board.

       Disregard the W6 jumper installation instructions in the computer
       user's guide.  Refer instead to the following W6 Upgrade Processor
       Support Jumper settings:

┌────────────────────┬──────────┬────────────────────────────────────────┐
│Function            │ Settings │ Options                                │
├────────────────────┼──────────┼────────────────────────────────────────┤
│Upgrade Processor   │   2-3*   │ i486 SX, i486 DX2 ODP, and i486 DX4 ODP│
│Support             │          │ supported.                             │
├────────────────────┼──────────┼────────────────────────────────────────┤
│                    │   1-2    │ i486 DX, i487 SX, i486 DX2 ODPR, and   │
│                    │          │ i486 DX4 ODPR supported.               │
├────────────────────┴──────────┴────────────────────────────────────────┤
│ *Indicates the default setting.                                        │
└────────────────────────────────────────────────────────────────────────┘

The following diagram shows the locations of the jumper blocks on the Main
Logic Board:

         ┌─────────────────────────────────────────────────────┐
         │ ┌─────┐ ┌──────────┐┌────┐┌────┐ ┌──┐┌──┐           │
         │ │     │ └──────────┘└────┘└────┘ └──┘└──┘           │
On-Board │ └─────┘                    ┌─┐                    ┌┐│
Video────┼──────────────>┌┬┐          │ │                    │││
Interrupt│               └┴┘          │ │                    │││
(W9)     │           ┌───────┐┌┐ ┌─┐  │ │                    └┘│
         │┌─┐        │    ┌──>├┤ │ │  │ │     ┌──┐           ┌┐│
On-Board─┼┼─┼────────┼────┘  │└┘ │ │  │ │     │  │           │││
Video    ││ │        │       │   │ │  │ │     │  │           │││
Enable   ││ │ ┌┐ ┌┐  │       │   │ │  │ │     └──┘           │││
(W8)     ││ │ ││ ││  └───────┘   │ │  │ │    ┌┬┬┐<───────────┴┴┼Serial
         │└─┘ └┘ └┘              └─┘  │ │    ├┼┼┤              │Port
         │           ┌┐ ┌┐ ┌┐ ┌┐      │ │    ├┼┼┤         ┌─┐  │Interrupt
         │    ┌┐ ┌┐  ││ ││ ││ ││      │ │    └┼┴┘         │ │┌┐│(W3, W4)
         │    ││ ││  ││ ││ ││ ││      │ │ ┌──┐└───────────┼─┼┼┼┼Parallel
         │    └┘ └┘  ││ ││ ││ ││      │ │ │  │            │ ││││Port
         │           └┘ └┘ └┘ └┘      │ │ └──┘            │ │└┘│Interrupt
         │ ┌─────────┐                │ │                 └─┘  │(W5)
         │ │┌───────┐│  ┌─────────┐   │ │                      │
         │ ││       ││  │         │   │ │                      │
         │ ││       ││  │         │   │ │  ┌───┐               │
         │ ││       ││  │         │   │ │  │   │               │
         │ ││       ││  │         │   └─┘  │   │  ┌┬┐<─────────┼Power
         │ ││       ││  │         │        └───┘  └┴┘          │Indicator
Upgrade  │ └└───────┴┘  └─────────┘             ┌──┐           │Harddrive
Processor┼────────────────>┌┬┬┐                 └──┘           │Activity
Support  │                 └┴┴┘                                │Indicator
(W7)     │                   ┌┬┬┐                              │(W2)
         │┌─────────────────>└┴┴┘             ┌─────────┐┌┬┐<──┼Clock
Upgrade  ││                                   │         │└┴┘   │Speed
Processor┼┘ ─────────────────────────         │         │      │(W1)
Support  │                                    │         │      │
(W6)     │  ─────────────────────────         │         │      │
         │                                    │         │      │
         │  ─────────────────────────         └─────────┘      │
         │                                                     │
         │  ─────── ───────── ───────                          │
         │                                                     │
         │      ┌──┐┌────┐┌──┐┌────┐                           │
         │      └──┘└────┘└──┘└────┘                           │
         └─────────────────────────────────────────────────────┘
                              Front of Computer

(smc/tmc/BKL-02/08/96)