TANDY/RADIO SHACK

4025 LX (250-5125), 4033 LX

Processor                  80386
Processor Speed            25MHz
Chip Set                   Unidentified
Video Chip Set             None
Maximum Onboard Memory     16MB (on external memory cards)
Maximum Video Memory       None
Cache                      32KB
BIOS                       Unidentified
Dimensions                 355mm x 304mm
I/O Options                External memory cards (2) CPU slot, floppy
                           drive interface, IDE interface, parallel port,
                           PS/2 mouse port, serial port
NPU Options                80387/3167

[Image]

                                CONNECTIONS

  Purpose                   Location    Purpose                 Location

  PS/2 mouse port             CN1       External battery          CN6

  Serial port                 CN2       Speaker                   CN7

  Parallel port               CN3       External memory         SL1 & SL2
                                        cards

  IDE interface               CN4       CPU slot                  SL3

  Floppy drive interface      CN5

                        USER CONFIGURABLE SETTINGS

                Function                     Label           Position

  »   Monitor type select through              J1           Pins 2 & 3
      software                                                closed

      Monitor type select color                J1           Pins 1 & 2
                                                              closed

      Monitor type select monochrome           J1              Open

  »   IDE IOCHRDY enabled                      J4             Closed

      IDE IOCHRDY disabled                     J4              Open

  »   IDE DIAG normal operation                J5              Open

      IDE DIAG diagnostic mode                 J5             Closed

  »   I/O recovery mode enabled                J6             Closed

      I/O recovery mode disabled               J6              Open

  »   Factory configured - do not alter        J7             Closed

  »   Factory configured - do not alter        J8             Closed

  »   Factory configured - do not alter        J9             Closed

                            DRAM CONFIGURATION

     Size         Bank 0         Bank 1         Bank 2         Bank 3

     1MB       (4) 256K x 9       None           None           None

     2MB       (4) 256K x 9   (4) 256K x 9       None           None

     4MB        (4) 1M x 9        None           None           None

     8MB        (4) 1M x 9     (4) 1M x 9        None           None

     4MB       (4) 256K x 9   (4) 256K x 9   (4) 256K x 9   (4) 256K x 9

     10MB       (4) 1M x 9     (4) 1M x 9    (4) 256K x 9   (4) 256K x 9

     16MB       (4) 1M x 9     (4) 1M x 9     (4) 1M x 9     (4) 1M x 9

            Note: Banks 0 & 1 are located on the first memory card and
            banks 2 & 3 are located on the second memory card.

                   CACHE CONFIGURATION

  Note: The location of the 32KB cache is unidentified.

                              BIOS SELECTION

          Setting                     J2                     J3

             27128                   Open                   Open

  »          27256                  Closed                 Closed

             27512                   Open                  Closed

                       MISCELLANEOUS TECHNICAL NOTE

            Jumpers are labeled for information and location purposes
            only. The purpose of SL4 is unidentified.