
UNIDENTIFIED

486SX-DX MAINBOARD

Processor         80486SX/80487SX/80486DX/80486DX2
Processor Speed   33/40/50/66(internal)MHz
Chip Set          Unidentifed
Max. Onboard DRAM 32MB
Cache             None
BIOS              Award
Dimensions        254mm x 220mm
I/O Options       Floppy drive interface, IDE interface, parallel port,
                  PS/2 mouse port, serial ports (2), VGA port
NPU Options       None

[Image]

                                CONNECTIONS

  Purpose                Location      Purpose                 Location

  VGA port                  CN1        Power LED & keylock        J1

  Parallel port             CN2        Turbo switch           J2 pins 1 &
                                                                  2

  Serial port 1             CN3        Turbo LED              J2 pins 4 &
                                                                  5

  Serial port 2             CN4        Speaker                    J3

  PS/2 mouse port           CN5        Reset switch               J4

  IDE interface             CN6        IDE interface LED          J5

  Floppy drive              CN7        Riser Card                SL1
  interface

                        USER CONFIGURABLE SETTINGS

                 Function                     Jumper         Position

     Video mode select interlaced             JP7            Closed

      Video mode select non-interlaced         JP7             Open

     Monitor type select monochrome           JP10           Closed

      Monitor type select color                JP10            Open

     CPU OSC select 66MHz                     jp11          pins 2 & 3
                                                              closed

      CPU OSC select 50MHz                     jp11          pins 1 & 2
                                                              closed

     On board VGA enabled                     JP12          pins 2 & 3
                                                              closed

      On board VGA disabled                    JP12          pins 1 & 2
                                                              closed

     Monitor type select VESA                 JP14          pins 2 & 3
                                                              closed

      Monitor type select VGA                  JP14          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

      32MB        (4) 4M x 9      (4) 4M x 9

                    CPU TYPE CONFIGURATION

        Type                 JP4                  JP5

       80486SX               Open          pins 1 & 2 closed

       80487SX         pins 1 & 2 closed   pins 2 & 3 closed

       80486DX         pins 2 & 3 closed   pins 2 & 3 closed

      80486DX2         pins 2 & 3 closed   pins 2 & 3 closed

                   CPU SPEED CONFIGURATION

        Speed                JP3                  JP6

        33MHz          pins 2 & 3 closed   pins 2 & 3 closed

        40MHz          pins 2 & 3 closed   pins 1 & 2 closed

        50MHz          pins 1 & 2 closed   pins 2 & 3 closed

       66iMHz          pins 1 & 2 closed   pins 1 & 2 closed

