This document is for the baby-sized (8.5" x 13.3") 386SX-20 and 386SX-25 non-cached
motherboard. The part number for this board is 09-00105-xx.
It's identifying features are: an LED between expansion slots #5 and #6; six 16-bit
expansion slots, and two 8-bit expansion slots; eight sockets for SIMMs (four banks of 2);
a socket for a 80387SX coprocessor.
The bus speed for this motherboard is fixed at 8MHz.
+=============================+
+ +
+ MOTHERBOARD JUMPER SETTINGS +
+ +
+=============================+
J1 External keyboard connector
Pin 1 - Keyboard clock
Pin 2 - Keyboard data
Pin 3 - no connector
Pin 4 - Ground
Pin 5 - +5 volts DC
J13 Monitor type
Not connected Color video card
Connected Monochrome video card
J14 Coprocessor configuration
Pins 1-2 Coprocessor installed
Not connected Coprocessor not installed
J15 80386 Pipeline configuration
Connected 80386 pipeline access
Not connected 80386 non-pipeline access
J24 External 6-volt battery connector
Pin 1 - Battery Positive
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - Ground
J28 Turbo switch
Pin 1 - Signal
Pin 2 - Ground
J29 Turbo LED
Pin 1 - Signal
Pin 2 - Ground
J30 Reset switch
Pin 1 - Signal
Pin 2 - Ground
J31 External speaker
Pin 1 - Speaker
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - +5 volts DC
J32 Keylock / Power LED
Pin 1 - Power LED signal
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - Keyboard lock signal
Pin 5 - Ground
+========================+
+ +
+ MEMORY CONFIGURATION +
+ +
+========================+
Listed below are the possible memory configurations
Size
in Bank Bank Bank Bank
MB 0 1 2 3
-----------------------------------
0.5 256K
1.0 256K 256K
1.5 256K 256K 256K
2.0 256K 256K 256K 256K
2.0 1MB
2.5 256K 1MB
3.0 256K 256K 1MB
4.0 1MB 1MB
4.5 256K 1MB
5.0 256K 1MB
6.0 1MB 1MB 1MB
8.0 1MB 1MB 1MB 1MB
8.0 4MB
8.5 256K 4MB
9.0 256K 256K 4MB
10.0 1MB 4MB
12.0 1MB 1MB 4MB
16.0 4MB 4MB
256K = Two 256Kx9 SIMMs in the bank
1MB = Two 1Mx9 SIMMs in the bank
4MB = Two 4Mx9 SIMMs in the bank