80486xx VL 486V (Baby size 09-00169-xx)

This document is for the baby-sized (13.3" x 8.5") 486V VL-Bus motherboard.

The part number for this board is 09-00169-xx.

It's identifying features are: an LED between expansion slots #5 and #6; eight 16-bit

expansion slots; two 16-bit/VL-Bus expansion slots; four sockets for 72 pin SIMMs; a ZIF socket

for a 486 or Pentium OverDrive CPU; one external cache socket (SL3). Two IDE interface connectors; one floppy connector;

two serial port connectors; one parallel port connector. AT (DIN) style keyboatd connector. 8 position DIP switch (SW8)

located to the right of the ZIF socket.

The VESA Local Bus speed is determined by the CPU speed. If the CPU is a 486SX-25, or 486DX2-50, the VL-Bus

bus speed is 25MHz. If the CPU is a 486SX-33, 486DX-33, or 486DX2-66, the VL-Bus

bus speed is 33MHz. A 50 MHZ CLK is not yet a current VESA standard specification

The ISA bus speed for this motherboard is set at 8.33MHz. The CPU clock speed is

determined by Sw-8 5 thru 8.

The following shows all of the possible memory configurations.

Processor upgrade report:

<jtob@desupernet.net> Jim O'brien has successfully upgraded this MB with the Cyrix 586-100 purchased from Ben Myers at

benmyers@ultranet.com He removed the 486 CPU from the PGA socket and installed the upgrade in the ZIF socket.

Returns a Norton benchmark equivalent to a Pentium 75. The BIOS was upgraded using the Microfirmware M4GS25 revision prior

to the CPU upgrade. Per Ben Myers, the MFI BIOS is a MUST for it to recognize the Cyrix CPU correctly.

Boot halts will occur without the MFI BIOS.


DIP switch settings for memory size.

Sw8-1 Sw8-2 Sw8-3 Sw8-4

4MB On On On On

8MB Off On On On

12MB On Off On On

16MB Off Off On On

16MB On On Off On

20MB On On Off Off

24MB On Off On Off

28MB Off On On Off

32MB Off On Off On

36MB On Off Off Off

40MB Off Off On Off

48MB On Off Off On

52MB Off Off Off Off

64MB Off Off Off On


Memory Banks 36 bit parity SIMM's.


MB 0 1 2 3

---- ---- ---- ---- ----

4MB 1 x 36

8MB 1 x 36 1 x 36

12MB 1 x 36 1 x 36 1 x 36

16MB 1 x 36 1 x 36 1 x 36 1 x 36

16MB 4 x 36

20MB 1 x 36 4 x 36

24MB 1 x 36 1 x 36 4 x 36

28MB 1 x 36 1 x 36 1 x 36 4 x 36

32MB 4 x 36 4 x 26

36MB 1 x 36 4 x 36 4 x 36

40MB 1 x 36 1 x 36 4 x 36 4 x 36

48MB 4 x 26 4 x 36 4 x 36

52MB 1 x 36 4 x 36 4 x 36 4 x 36

64MB 4 x 36 4 x 36 4 x 36 4 x 36

In the table above, 1M indicates that one 256x36 SIMM is installed in the socket,

4M indicates that one 1Mx36 SIMM is installed in the socket, 16M indicates that,

one 4Mx36 SIMM is installed in the socket.

Micronics Computers has tested and verified the following 1Mx36 memory brands:

Micron Technologies, Mitsubishi, Samsung, Texas Instruments, Toshiba

Micronics Computers has tested and verified the following 4Mx36 memory brands:

Mitsubishi, Samsung, Toshiba


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DIP switch settings for CPU selection


DIP Switch 8


CPU Speed sw8- Sw8-6 Sw8-7 Sw8-8






W22 1-2 CPU type = 486DX/DX2

W22 2-3 CPU type = Pentium overdrive.

W23 1-2 CPU type = 486SX (DO NOT INSTALL IN ZIF socket.

W23 2-3 CPU type = non 486SX

J11 Serial 16550 Port A National Semiconductor Super i/o PC87312

J12 Parallel Printer Port

J14 Serial 16550 Port B National Semiconductor Super i/o PC87312

J15 FDD interface

J16 Primary IDE interface

J24 External battery

The external battery is not required.

The Dallas / Benchmarq Real Time Clock Chip contains an internal battery for an approximate lifetime of 8-10 years.

J 28 Speaker

J 29 Power LED and keylock

J30 Secondary IDE interface

J 36 external keyboard

W15 Reset switch

W17 Turbo LED

W18 Turbo switch

W 19 IDE interface LED

SL1 & SL2 32 bit VESA local bus slots

SL3 External cache card slot. 80 pin. Looks like SIMM connector.


COM1 3F8h IRQ 4

COM2 2F8h 3

COM3 3E8h 4

COM4 2E8h 3

LPT1 3BCh 7

LPT2 378h 7

LPT3 278h 7

IRQ in use


IRQ 6 Floppy controller

IRQ 14 Primary IDE controller

W16 1-2 Parallel port unidirectional (printer)

W16 2-3 Parallel port bi directional.

W20 1-2 Flash BIOS write protected

W20 2-3 Flash BIOS write enabled.


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+ Cache Configuration +

+ 80 pin external cache card. (not memory SIMM))

64/128/256KB on external cache card.+

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