This document is for the full-sized (13.8" x 12.025") 80486 ASIC ISA 486-33 motherboard. The part number for this board is 09-00054-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 Reserved *Off 2 Reserved *Off 3 Reserved *Off 4 Reserved *Off 5 Reserved *Off 6 Reserved *Off 7 Video Bios cacheable *Off Video Bios non-cacheable On 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 Memory size (See below) 6 80ns DRAM installed On 70ns DRAM installed *Off 7 64K or 256K cache Off 128K cache On 8 64K cache Off 128K or 256K cache On DIP switch settings for memory size =================================== Memory Banks DIP Switch 2 --------------------------------------------------- MB 0 1 2 3 S1 S2 S3 S4 S5 ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 1MB 256K ON ON ON ON ON 2MB 256K 256K OFF ON ON ON ON 3MB 256K 256K 256K ON OFF ON ON ON 4MB 256K 256K 256K 256K OFF OFF ON ON ON 4MB 1MB ON ON OFF ON ON 5MB 256K 1MB ON ON OFF OFF ON 6MB 256K 256K 1MB ON OFF ON OFF ON 7MB 256K 256K 256K 1MB OFF ON ON OFF ON 8MB 1MB 1MB OFF ON OFF ON ON 9MB 256K 1MB 1MB ON OFF OFF OFF ON 10MB 256K 256K 1MB 1MB OFF OFF ON OFF ON 12MB 1MB 1MB 1MB ON OFF OFF ON ON 13MB 256K 1MB 1MB 1MB OFF OFF OFF OFF ON 16MB 1MB 1MB 1MB 1MB OFF OFF OFF ON ON 16MB 4MB ON ON OFF ON OFF 20MB 1MB 4MB ON ON OFF OFF OFF 24MB 1MB 1MB 4MB ON OFF ON OFF OFF 28MB 1MB 1MB 1MB 4MB OFF ON ON OFF OFF 32MB 4MB 4MB OFF ON OFF ON OFF 36MB 1MB 4MB 4MB ON OFF OFF OFF OFF 40MB 1MB 1MB 4MB 4MB OFF OFF ON OFF OFF 48MB 4MB 4MB 4MB ON OFF OFF ON OFF 52MB 1MB 4MB 4MB 4MB OFF OFF OFF OFF OFF 64MB 4MB 4MB 4MB 4MB OFF OFF OFF ON OFF In the table above, 256K indicates that four 256Kx9 SIMMs are installed in the bank, 1MB indicates that four 1Mx9 SIMMs are installed in the bank, and 4MB indicates that four 4Mx9 SIMMs are installed in the bank. The above shows all of the possible memory configurations. When installing more than 16MB of memory, BIOS relocation must be disabled. Bios relocation copies the video Bios (C0000-C7FFF) and the system ROM Bios (F0000-FFFFF) into RAM. The motherboard adds 15MB to these addresses (F00000) to be able to differentiate between the ROM and RAM. Enabling the relocation feature causes the memory above 16MB to become non-contiguous and therefore inaccessible. Micronics Computers has tested and verified the following memory brands: Toshiba, Siemens, Mitsubishi, NEC +=============================+ + + + MOTHERBOARD JUMPER SETTINGS + + + +=============================+ J13 External 6-volt battery connector Pin 1 - Battery Positive Pin 2 - no connector Pin 3 - Ground Pin 4 - Ground J30 External speaker Pin 1 - Speaker Pin 2 - no connector Pin 3 - Ground Pin 4 - +5 volts DC J31 Keylock / Power LED Pin 1 - Power LED signal Pin 2 - no connector Pin 3 - Ground Pin 4 - Keyboard lock signal Pin 5 - Ground W4 Reserved Pins 1-2 W5 Cache configuration Installed - 128K or 256K Not installed - 64K W6 Cache configuration Installed - 256K Not installed - 64K or 128K W7 Reserved W9 Turbo LED Pin 1 - Signal Pin 2 - Ground W10 Reset switch Pin 1 - Signal Pin 2 - Ground W11 Turbo switch Pin 1 - Signal Pin 2 - Ground