
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 DRAM32MB
Cache            64/128/256KB
BIOS             AMI
Dimensions       330mm x 218mm
I/O Options      None
NPU Options      4167

[Image]

                                CONNECTIONS

  Purpose                   Location   Purpose                   Location

  External battery            J1       Speaker                     J4

  Turbo LED                   J2       Power LED & keylock         J5

  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.

