This document is for the full-sized (13.8" x 12.025") 486-25 ISA motherboard. The part number for this board is 09-00025-xx. It's identifying features are: an LED between expansion slots #5 and #6; eight 16-bit expansion slots; sixteen sockets for SIMMs (four banks of 4); a socket for a Weitek 4167 coprocessor. The bus speed for this motherboard is fixed at 8MHz. +=============================+ + + + MOTHERBOARD SWITCH SETTINGS + + + + * = Default setting + +=============================+ SW1 --- 1 Internal cache enabled *On Internal cache disabled Off 2 Enable on-board Bios *Off Enable external Bios On 3 Reserved *On 4 External cache enabled *On External cache disabled Off 5 Bios relocation enabled On Bios relocation disabled *Off 6 Reserved *Off 7 CGA / EGA / VGA *On Monochrome Off 8 Reserved *Off SW2 --- 1 Memory size (see below) 2 Memory size (see below) 3 Memory size (see below) 4 Memory size (see below) 5 Reserved *Off 6 D00000-EFFFFF cacheable *Off D00000-EFFFFF non-cacheable On 7 64K or 256K external cache Off 128K external cache On 8 64K external cache Off 128K or 256K external cache On DIP switch settings for memory size =================================== Memory Banks DIP Switch 2 ----------------------------------------------- MB 0 1 2 3 S1 S2 S3 S4 ---- ---- ---- ---- ---- ---- ---- ---- ---- 1MB 256K ON ON ON ON 2MB 256K 256K OFF ON ON ON 3MB 256K 256K 256K ON OFF ON ON 4MB 256K 256K 256K 256K OFF OFF ON ON 4MB 1MB ON ON OFF ON 5MB 256K 1MB ON ON OFF OFF 6MB 256K 256K 1MB ON OFF ON OFF 7MB 256K 256K 256K 1MB OFF ON ON OFF 8MB 1MB 1MB OFF ON OFF ON 9MB 256K 1MB 1MB ON OFF OFF OFF 10MB 256K 256K 1MB 1MB OFF OFF ON OFF 12MB 1MB 1MB 1MB ON OFF OFF ON 13MB 256K 1MB 1MB 1MB OFF OFF OFF OFF 16MB 1MB 1MB 1MB 1MB OFF OFF OFF ON In the table above, 256K indicates that four 256Kx9 SIMMs are installed in the bank, and 1MB indicates that four 1Mx9 SIMMs are installed in the bank. The above shows all of the possible memory configurations. The maximum amount of memory supported by this board is 16MB. Micronics Computers has tested and verified the following memory brands: Toshiba, Siemens, Mitsubishi, NEC +=============================+ + + + MOTHERBOARD JUMPER SETTINGS + + + +=============================+ J2 External 6-volt battery connector Pin 1 - Battery Positive Pin 2 - no connector Pin 3 - Ground Pin 4 - Ground J22 External speaker Pin 1 - Speaker Pin 2 - no connector Pin 3 - Ground Pin 4 - +5 volts DC J23 Keylock / Power LED Pin 1 - Power LED signal Pin 2 - no connector Pin 3 - Ground Pin 4 - Keyboard lock signal Pin 5 - Ground W2 Reserved Pins 2-3 W4 Reset switch Pin 1 - Signal Pin 2 - Ground W5 Turbo LED Pin 1 - Signal Pin 2 - Ground W6 Turbo switch Pin 1 - Signal Pin 2 - Ground W8 External cache configuration Pins 1-2 - 64K Pins 2-3 - 128K or 256K W9 External cache configuration Pins 1-2 - 64K or 128K Pins 2-3 - 256K