UNIDENTIFIED
============

   50/33/25/20MHZ MAINBOARD

   Processor         80486SX/80487SX/80486DX/80486DX2             
   Processor Speed   20/25/33/40/50 (Internal) /50/66 (Internal)  
   Chip Set          C & T                                        
   Max. onboard DRAM 32MB                                         
   Cache             64/128/256KB                                 
   BIOS              AMI                                          
   Dimensions        330mm x 218mm                                
   I/O Options       None                                         
   NPU Options       None                                         

<gopher://bitreich.org/I/th99/m/U-Z/31631-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose           | Location | Purpose          | Location |
   |-------------------+----------+------------------+----------|
   | Power LED &       |   J17    | External battery |   J20    |
   | keylock           |          |                  |          |
   |-------------------+----------+------------------+----------|
   | Speaker           |   J18    | Turbo switch     |   J21    |
   |-------------------+----------+------------------+----------|
   | Reset switch      |   J19    | Turbo LED        |   J22    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |           Function            | Jumper/Switch |  Position  |
   |-------------------------------+---------------+------------|
   |>> | Monitor type select       |      JP3      |    Open    |
   |   | monochrome                |               |            |
   |---+---------------------------+---------------+------------|
   |   | Monitor type select color |      JP3      |   Closed   |
   |---+---------------------------+---------------+------------|
   |>> | CMOS memory normal        |      JP5      | Pins 1 & 2 |
   |   | operation                 |               |   closed   |
   |---+---------------------------+---------------+------------|
   |   | CMOS memory clear         |      JP5      | Pins 2 & 3 |
   |   |                           |               |   closed   |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                     DRAM CONFIGURATION                     |
   |------------------------------------------------------------|
   |       Size       |       Bank 0       |       Bank 1       |
   |------------------+--------------------+--------------------|
   |       1MB        |    (4) 256K x 9    |        NONE        |
   |------------------+--------------------+--------------------|
   |       2MB        |    (4) 256K x 9    |    (4) 256K x 9    |
   |------------------+--------------------+--------------------|
   |       4MB        |     (4) 1M x 9     |        NONE        |
   |------------------+--------------------+--------------------|
   |       5MB        |    (4) 256K x 9    |     (4) 1M x 9     |
   |------------------+--------------------+--------------------|
   |       8MB        |     (4) 1M x 9     |     (4) 1M x 9     |
   |------------------+--------------------+--------------------|
   |       16MB       |     (4) 4M x 9     |        NONE        |
   |------------------+--------------------+--------------------|
   |       20MB       |     (4) 1M x 9     |     (4) 4M x 9     |
   |------------------+--------------------+--------------------|
   |       32MB       |     (4) 4M x 9     |     (4) 4M x 9     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                    CACHE CONFIGURATION                     |
   |------------------------------------------------------------|
   | Size  |     Max     |   Bank 0   |   Bank 1   |    TAG     |
   |       |  Cachable   |            |            |            |
   |-------+-------------+------------+------------+------------|
   | 64KB  |    16MB     | (4) 8K x 8 | (4) 8K x 8 | (1) 8K x 8 |
   |-------+-------------+------------+------------+------------|
   | 128KB |    32MB     | (4) 32K x  |    NONE    | (1) 8K x 8 |
   |       |             |     8      |            |            |
   |-------+-------------+------------+------------+------------|
   | 256KB |    64MB     | (4) 32K x  | (4) 32K x  | (1) 32K x  |
   |       |             |     8      |     8      |     8      |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 CACHE JUMPER CONFIGURATION                 |
   |------------------------------------------------------------|
   |       Size       |        JP24        |        JP25        |
   |------------------+--------------------+--------------------|
   |       64KB       |        Open        |        Open        |
   |------------------+--------------------+--------------------|
   |      128KB       | Pins 1 & 2 closed  | Pins 1 & 2 closed  |
   |------------------+--------------------+--------------------|
   |      256KB       | Pins 2 & 3 closed  | Pins 2 & 3 closed  |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |           Speed            |             JP21              |
   |----------------------------+-------------------------------|
   |       80486SX/20MHz        |       Pins 5 & 6 closed       |
   |----------------------------+-------------------------------|
   |       80486SX/25MHz        |   Pins 1 & 2, 5 & 6 closed    |
   |----------------------------+-------------------------------|
   |       80486SX/33MHz        |   Pins 1 & 2, 3 & 4 closed    |
   |----------------------------+-------------------------------|
   |       80487SX/20MHz        |       Pins 5 & 6 closed       |
   |----------------------------+-------------------------------|
   |       80486DX/25MHz        |   Pins 1 & 2, 5 & 6 closed    |
   |----------------------------+-------------------------------|
   |       80486DX/33MHz        |   Pins 1 & 2, 3 & 4 closed    |
   |----------------------------+-------------------------------|
   |       80486DX/40MHz        |       Pins 5 & 6 closed       |
   |----------------------------+-------------------------------|
   |       80486DX/50MHz        |       Pins 3 & 4 closed       |
   |----------------------------+-------------------------------|
   |      80486DX2/50i MHz      |   Pins 1 & 2, 5 & 6 closed    |
   |----------------------------+-------------------------------|
   |      80486DX2/66i MHz      |   Pins 1 & 2, 3 & 4 closed    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   |     TYPE      |    JP9    |  JP11  |   JP12    |   JP13    |
   |---------------+-----------+--------+-----------+-----------|
   | 80486SX/20MHz | Pins 2 &  |  Open  | Pins 2 &  | Pins 2 &  |
   |               | 3 closed  |        | 3 closed  | 3 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486SX/25MHz | Pins 1 &  |  Open  | Pins 2 &  | Pins 2 &  |
   |               | 2 closed  |        | 3 closed  | 3 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486SX/33MHz | Pins 1 &  |  Open  | Pins 2 &  | Pins 2 &  |
   |               | 2 closed  |        | 3 closed  | 3 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80487SX/20MHz | Pins 2 &  | Closed | Pins 2 &  | Pins 1 &  |
   |               | 3 closed  |        | 3 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX/25MHz | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |               | 2 closed  |        | 2 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX/33MHz | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |               | 2 closed  |        | 2 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX/40MHz | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |               | 2 closed  |        | 2 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX/50MHz | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |               | 2 closed  |        | 2 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX2/50i  | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |      MHz      | 2 closed  |        | 2 closed  | 2 closed  |
   |---------------+-----------+--------+-----------+-----------|
   | 80486DX2/66i  | Pins 1 &  | Closed | Pins 1 &  | Pins 1 &  |
   |      MHz      | 2 closed  |        | 2 closed  | 2 closed  |
   +------------------------------------------------------------+