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       # UNIDENTIFIED
       
          486SX/DX/DX2-MAINBOARD
       
          Processor             80486SX/80486DX/80486DX2                 
          Processor Speed       20/25/33/50(internal)/50/66(internal)MHz 
          Chip Set              UNI                                      
          Video Chip Set        None                                     
          Maximum Onboard       32MB                                     
          Memory                
          Maximum Video Memory  None                                     
          Cache                 64/128/256KB                             
          BIOS                  AMI                                      
          Dimensions            260mm x 220mm                            
          I/O Options           32-bit VESA local bus slots (3)          
          NPU Options           None                                     
       
   IMG IMG 1
          
       
          +------------------------------------------------------------+
          |                        CONNECTIONS                         |
          |------------------------------------------------------------|
          | Purpose       | Location | Purpose              | Location |
          |---------------+----------+----------------------+----------|
          | Turbo switch  |    H1    | Reset switch         |    H5    |
          |---------------+----------+----------------------+----------|
          | Turbo LED     |    H2    | External battery     |    J1    |
          |---------------+----------+----------------------+----------|
          | Power LED &   |    H3    | 32-bit VESA local    |  SL1 -   |
          | keylock       |          | bus slots            |   SL3    |
          |---------------+----------+----------------------+----------|
          | Speaker       |    H4    |                      |          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                 USER CONFIGURABLE SETTINGS                 |
          |------------------------------------------------------------|
          |               Function                | Label |  Position  |
          |---------------------------------------+-------+------------|
          | » | Turbo enabled                     |  H1   |   Closed   |
          |---+-----------------------------------+-------+------------|
          |   | Turbo enabled through keyboard    |  H1   |    Open    |
          |   | (CTRL, ALT, +)                    |       |            |
          |---+-----------------------------------+-------+------------|
          |   | Turbo disabled through keyboard   |  H1   |    Open    |
          |   | (CTRL, ALT, -)                    |       |            |
          |---+-----------------------------------+-------+------------|
          | » | CMOS memory normal operation      |  J1   | Pins 2 & 3 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | CMOS memory clear                 |  J1   | Pins 3 & 4 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | Battery type select external      |  J1   |   Closed   |
          |---+-----------------------------------+-------+------------|
          | » | Monitor type select color         |  J3   |   Closed   |
          |---+-----------------------------------+-------+------------|
          |   | Monitor type select monochrome    |  J3   |    Open    |
          |---+-----------------------------------+-------+------------|
          | » | VL-BUS clock normal operation     | JP43  | Pins 2 & 3 |
          |   |                                   |       |   closed   |
          |---+-----------------------------------+-------+------------|
          |   | VL-BUS clock adjusted             | JP43  | Pins 1 & 2 |
          |   |                                   |       |   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     |
          |------------------+--------------------+--------------------|
          |       20MB       |     (4) 4M x 9     |     (4) 1M x 9     |
          |------------------+--------------------+--------------------|
          |       32MB       |     (4) 4M x 9     |     (4) 4M x 9     |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                    CACHE CONFIGURATION                     |
          |------------------------------------------------------------|
          |    Size    |    Bank 0     |    Bank 1     |      TAG      |
          |------------+---------------+---------------+---------------|
          |    64KB    |  (4) 8K x 8   |  (4) 8K x 8   |  (1) 8K x 8   |
          |------------+---------------+---------------+---------------|
          |   128KB    |  (4) 32K x 8  |     None      |  (1) 8K x 8   |
          |------------+---------------+---------------+---------------|
          |   256KB    |  (4) 32K x 8  |  (4) 32K x 8  |  (1) 32K x 8  |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                 CACHE JUMPER CONFIGURATION                 |
          |------------------------------------------------------------|
          | Size  |  JP6   |  JP7   |  JP8   |           JP9           |
          |-------+--------+--------+--------+-------------------------|
          | 64KB  |  Open  | Closed |  Open  |    Pins 1 & 2 closed    |
          |-------+--------+--------+--------+-------------------------|
          | 128KB |  Open  | Closed | Closed |    Pins 1 & 2, 3 & 4    |
          |       |        |        |        |         closed          |
          |-------+--------+--------+--------+-------------------------|
          | 256KB | Closed | Closed | Closed |    Pins 1 & 2, 4 & 5    |
          |       |        |        |        |         closed          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                    CPU SPEED SELECTION                     |
          |------------------------------------------------------------|
          |     Speed     |     JP29     |     JP30     |     JP31     |
          |---------------+--------------+--------------+--------------|
          |     20MHz     |     Open     |    Closed    |     Open     |
          |---------------+--------------+--------------+--------------|
          |     25MHz     |    Closed    |     Open     |    Closed    |
          |---------------+--------------+--------------+--------------|
          |     33MHz     |    Closed    |    Closed    |     Open     |
          |---------------+--------------+--------------+--------------|
          |    50iMHz     |    Closed    |     Open     |    Closed    |
          |---------------+--------------+--------------+--------------|
          |     50MHz     |     Open     |    Closed    |     Open     |
          |---------------+--------------+--------------+--------------|
          |    66iMHz     |    Closed    |    Closed    |     Open     |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                     CPU TYPE SELECTION                     |
          |------------------------------------------------------------|
          |           Type           |               JP4               |
          |--------------------------+---------------------------------|
          |         80486SX          |        Pins 5 & 6 closed        |
          |--------------------------+---------------------------------|
          |         80486DX          | Pins 1 & 2, 4 & 5, 6 & 7 closed |
          |--------------------------+---------------------------------|
          |         80486DX2         | Pins 1 & 2, 4 & 5, 6 & 7 closed |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                VL BUS WAIT STATE SELECTION                 |
          |------------------------------------------------------------|
          |             Setting             |           JP20           |
          |---------------------------------+--------------------------|
          |        |           0            |           Open           |
          |--------+------------------------+--------------------------|
          | »      |           1            |          Closed          |
          +------------------------------------------------------------+
       
          +------------------------------------------------------------+
          |                   VL BUS SPEED SELECTION                   |
          |------------------------------------------------------------|
          |              Speed              |           JP19           |
          |---------------------------------+--------------------------|
          |    |          <= 33MHz          |           Open           |
          |----+----------------------------+--------------------------|
          | »  |          >33 MHz           |          Closed          |
          +------------------------------------------------------------+