UNIDENTIFIED

TURBO MAIN BOARD (426A)

Processor              8088
Processor Speed        4.77/8MHz
Chip Set               Unidentified
Video Chip Set         None
Maximum Onboard Memory 640KB
Maximum Video Memory   None
Cache                  None
BIOS                   Unidentified
Dimensions             330mm x 218mm
I/O Options            None
NPU Options            8087

[Image]

                                CONNECTIONS

  Purpose                 Location       Purpose              Location

  Turbo switch (to           JP5         Power LED           JP9 pins 3 &
  turbo switch                                                    4
  button)

  Turbo LED             JP9 pins 1 & 2   Speaker                 P4

                        USER CONFIGURABLE SETTINGS

               Function                   Label            Position

  »    Factory configured - do not         JP1           Unidentified
       alter

       Turbo enabled                       JP6              Closed

       Turbo disabled                      JP6               Open

       Turbo enabled (CTRL, ALT, +)        JP7              Closed

       Turbo disabled (CTRL, ALT, -)       JP7               Open

       Keyboard lock disabled              JP8              Closed

       Keyboard lock enabled               JP8               Open

  »    Factory configured - do not        SW1/1               Off
       alter

       NPU not installed                  SW1/2               On

       NPU installed                      SW1/2               Off

            Note: JP6 is for turbo selectable through hardware. JP7 is
            for turbo selectable through software. Both jumpers cannot be
            closed at the same time.

                       DRAM CONFIGURATION

    Size        Bank 0       Bank 1      Bank 2       Bank 3

  256KB (A)    (9) 4164     (9) 4164    (9) 4164     (9) 4164

  256KB (B)   (9) 41256       None        None         None

    512KB     (9) 41256    (9) 41256      None         None

    640KB     (9) 41256    (9) 41256    (9) 4164     (9) 4164

  Note: The location of banks 0, 1, 2, & 3 are unidentified.

                         DRAM JUMPER CONFIGURATION

         Size                     JP3                       JP4

       256KB (A)           Pins 1 & 3, 5 & 7         Pins 2 & 4 closed
                                closed

       256KB (B)           Pins 2 & 4, 6 & 8         Pins 1 & 3 closed
                                closed

         512KB             Pins 2 & 4, 6 & 8         Pins 1 & 3 closed
                                closed

         640KB             Pins 2 & 4, 6 & 8         Pins 1 & 3 closed
                                closed

  DRAM SWITCH CONFIGURATION

   Size     SW1/3     SW1/4

  128KB      Off       On

  192KB       On       Off

  256KB      Off       Off

                  FLOPPY DRIVE SELECTION

  Drives installed         SW1/7               SW1/8

         1                  On                  On

         2                  Off                 On

         3                  On                  Off

         4                  Off                 Off

                   MONITOR SELECTION

       Type              SW1/5              SW1/6

       None                On                 On

  Color (40 x 20)         Off                 On

  Color (80 x 25)          On                Off

    Monochrome            Off                Off