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