PC BRAND
========

   486/25C CACHE MAINBOARD

   (MYSTERY MACHINE)

   Processor         80486SX                                      
   Processor Speed   25MHz                                        
   Chip Set          OPTI                                         
   Max. Onboard DRAM 16MB                                         
   Cache             128KB (on external cache card)               
   BIOS              AMI                                          
   Dimensions        330mm x 218mm                                
   I/O Options       External cache card                          
   NPU Options       4167                                         

<gopher://bitreich.org/I/th99/m/P-R/32903-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose             | Location | Purpose        | Location |
   |---------------------+----------+----------------+----------|
   | External battery    |    J1    | Turbo switch   |    J9    |
   |---------------------+----------+----------------+----------|
   | Power LED & keylock |    J6    | Turbo LED      |   J10    |
   |---------------------+----------+----------------+----------|
   | Speaker             |    J7    | External cache |   SL1    |
   |                     |          | slot           |          |
   |---------------------+----------+----------------+----------|
   | Reset switch        |    J8    |                |          |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |               Function               | Jumper |  Position  |
   |--------------------------------------+--------+------------|
   |>> | Battery type select internal     |   J1   | pins 2 & 3 |
   |   |                                  |        |   closed   |
   |---+----------------------------------+--------+------------|
   |   | Battery type select external     |   J1   |   Closed   |
   |---+----------------------------------+--------+------------|
   |>> | Monitor type select monochrome   |   J2   |    Open    |
   |---+----------------------------------+--------+------------|
   |   | Monitor type select color        |   J2   |   Closed   |
   |---+----------------------------------+--------+------------|
   |>> | Factory configured - do not      |   J3   |    N/A     |
   |   | alter                            |        |            |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   | Size |   Bank 0    |   Bank 1    |   Bank 2   |   Bank 3   |
   |------+-------------+-------------+------------+------------|
   | 1MB  | (4) 256K x  |    NONE     |    NONE    |    NONE    |
   |      |      9      |             |            |            |
   |------+-------------+-------------+------------+------------|
   | 2MB  | (4) 256K x  | (4) 256K x  |    NONE    |    NONE    |
   |      |      9      |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 3MB  | (4) 256K x  | (4) 256K x  | (4) 256K x |    NONE    |
   |      |      9      |      9      |     9      |            |
   |------+-------------+-------------+------------+------------|
   | 4MB  | (4) 256K x  | (4) 256K x  | (4) 256K x | (4) 256K x |
   |      |      9      |      9      |     9      |     9      |
   |------+-------------+-------------+------------+------------|
   | 4MB  | (4) 1M x 9  |    NONE     |    NONE    |    NONE    |
   |------+-------------+-------------+------------+------------|
   | 5MB  | (4) 256K x  | (4) 1M x 9  |    NONE    |    NONE    |
   |      |      9      |             |            |            |
   |------+-------------+-------------+------------+------------|
   | 5MB  | (4) 1M x 9  | (4) 256K x  |    NONE    |    NONE    |
   |      |             |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 6MB  | (4) 256K x  | (4) 256K x  | (4) 1M x 9 |    NONE    |
   |      |      9      |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 6MB  | (4) 256K x  | (4) 1M x 9  | (4) 256K x |    NONE    |
   |      |      9      |             |     9      |            |
   |------+-------------+-------------+------------+------------|
   | 6MB  | (4) 1M x 9  | (4) 256K x  | (4) 256K x |    NONE    |
   |      |             |      9      |     9      |            |
   |------+-------------+-------------+------------+------------|
   | 7MB  | (4) 256K x  | (4) 256K x  | (4) 1M x 9 | (4) 256K x |
   |      |      9      |      9      |            |     9      |
   |------+-------------+-------------+------------+------------|
   | 7MB  | (4) 256K x  | (4) 1M x 9  | (4) 256K x | (4) 256K x |
   |      |      9      |             |     9      |     9      |
   |------+-------------+-------------+------------+------------|
   | 7MB  | (4) 1M x 9  | (4) 256K x  | (4) 256K x | (4) 256K x |
   |      |             |      9      |     9      |     9      |
   |------+-------------+-------------+------------+------------|
   | 8MB  | (4) 1M x 9  | (4) 1M x 9  |    NONE    |    NONE    |
   |------+-------------+-------------+------------+------------|
   | 9MB  | (4) 256K x  | (4) 1M x 9  | (4) 1M x 9 |    NONE    |
   |      |      9      |             |            |            |
   |------+-------------+-------------+------------+------------|
   | 9MB  | (4) 1M x 9  | (4) 1M x 9  | (4) 256K x |    NONE    |
   |      |             |             |     9      |            |
   |------+-------------+-------------+------------+------------|
   | 9MB  | (4) 1M x 9  | (4) 256K x  | (4) 1M x 9 |    NONE    |
   |      |             |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 10MB | (4) 256K x  | (4) 256K x  | (4) 1M x 9 | (4) 1M x 9 |
   |      |      9      |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 10MB | (4) 256K x  | (4) 1M x 9  | (4) 1M x 9 | (4) 256K x |
   |      |      9      |             |            |     9      |
   |------+-------------+-------------+------------+------------|
   | 10MB | (4) 1M x 9  | (4) 1M x 9  | (4) 256K x | (4) 256K x |
   |      |             |             |     9      |     9      |
   |------+-------------+-------------+------------+------------|
   | 10MB | (4) 1M x 9  | (4) 256K x  | (4) 1M x 9 | (4) 256K x |
   |      |             |      9      |            |     9      |
   |------+-------------+-------------+------------+------------|
   | 12MB | (4) 1M x 9  | (4) 1M x 9  | (4) 1M x 9 |    NONE    |
   |------+-------------+-------------+------------+------------|
   | 13MB | (4) 256K x  | (4) 1M x 9  | (4) 1M x 9 | (4) 1M x 9 |
   |      |      9      |             |            |            |
   |------+-------------+-------------+------------+------------|
   | 13MB | (4) 1M x 9  | (4) 1M x 9  | (4) 1M x 9 | (4) 256K x |
   |      |             |             |            |     9      |
   |------+-------------+-------------+------------+------------|
   | 13MB | (4) 1M x 9  | (4) 256K x  | (4) 1M x 9 | (4) 1M x 9 |
   |      |             |      9      |            |            |
   |------+-------------+-------------+------------+------------|
   | 16MB | (4) 1M x 9  | (4) 1M x 9  | (4) 1M x 9 | (4) 1M x 9 |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                    CACHE CONFIGURATION                     |
   |------------------------------------------------------------|
   |            Size            |              SL1              |
   |----------------------------+-------------------------------|
   |           128KB            |        Card installed         |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 CACHE JUMPER CONFIGURATION                 |
   |------------------------------------------------------------|
   |     Setting      |         J4         |         J5         |
   |------------------+--------------------+--------------------|
   |    Cache mode    | pins 1 & 2 closed  | pins 1 & 2 closed  |
   |------------------+--------------------+--------------------|
   |    Burst mode    | pins 2 & 3 closed  | pins 2 & 3 closed  |
   +------------------------------------------------------------+