CHAINTECH COMPUTER COMPANY, LTD.
================================

   420SXB/425SXB/433SCB/450SCB

   Processor         80486SX/80487SX/80486DX/ODP486SX/80486DX2    
   Processor Speed   16/20/25/33/50(internal)/50/66(internal)MHz  
   Chip Set          SIS                                          
   Max. Onboard DRAM 32MB                                         
   Cache             64/128/256KB                                 
   BIOS              AMI                                          
   Dimensions        330mm x 218mm                                
   I/O Options       None                                         
   NPU Options       4167                                         

<gopher://bitreich.org/I/th99/m/C-D/32310-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   | Purpose          | Location | Purpose           | Location |
   |------------------+----------+-------------------+----------|
   | External battery |    J1    | Speaker           |    J4    |
   |------------------+----------+-------------------+----------|
   | Turbo LED        |    J2    | Power LED &       |    J5    |
   |                  |          | keylock           |          |
   |------------------+----------+-------------------+----------|
   | Turbo switch     |    J3    | Reset switch      |    J6    |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |               Function               | Jumper  | Position  |
   |--------------------------------------+---------+-----------|
   |>> | Turbo enabled                    |   J3    |  Closed   |
   |---+----------------------------------+---------+-----------|
   |   | Turbo disabled                   |   J3    |   Open    |
   |---+----------------------------------+---------+-----------|
   |>> | Monitor type select monochrome   |   J7    |   Open    |
   |---+----------------------------------+---------+-----------|
   |   | Monitor type select color        |   J7    |  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        |
   |------------------+--------------------+--------------------|
   |       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    |    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 |  RN12   |  RN15   |  RN16   |  RN17   |  RN18   |  RN19   |
 |-----+---------+---------+---------+---------+---------+---------|
 |64KB |Installed|Installed|   Not   |   Not   |   Not   |   Not   |
 |     |         |         |installed|installed|installed|installed|
 |-----+---------+---------+---------+---------+---------+---------|
 |128KB|   Not   |   Not   |   Not   |Installed|Installed|   Not   |
 |     |installed|installed|installed|         |         |installed|
 |-----+---------+---------+---------+---------+---------+---------|
 |256KB|   Not   |   Not   |Installed|   Not   |   Not   |Installed|
 |     |installed|installed|         |installed|installed|         |
 +-----------------------------------------------------------------+

   +------------------------------------------------------------+
   |                   CPU TYPE CONFIGURATION                   |
   |------------------------------------------------------------|
   |            Type            |              JP7              |
   |----------------------------+-------------------------------|
   |          80486SX           |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |          ODP486SX          |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |          80487SX           |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |          80486DX           |       pins 1 & 2 closed       |
   |----------------------------+-------------------------------|
   |          80486DX2          |       pins 1 & 2 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                  CPU SPEED CONFIGURATION                   |
   |------------------------------------------------------------|
   |           Speed            |              JP1              |
   |----------------------------+-------------------------------|
   |           16MHz            |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |           20MHz            |       pins 2 & 3 closed       |
   |----------------------------+-------------------------------|
   |          > 25MHz           |       pins 1 & 2 closed       |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                MISCELLANEOUS TECHNICAL NOTE                |
   |------------------------------------------------------------|
   | Note:If a Weitek coprocessor is desired, the optional      |
   | daughter board must be installed in CPU socket.            |
   +------------------------------------------------------------+