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486SX/DX/DX2-MAINBOARD

UNIDENTIFIED

486SX/DX/DX2-MAINBOARD

Processor

80486SX/80486DX/80486DX2

Processor Speed

20/25/33/50(internal)/50/66(internal)MHz

Chip Set

UNI

Video Chip Set

None

Maximum Onboard Memory

32MB

Maximum Video Memory

None

Cache

64/128/256KB

BIOS

AMI

Dimensions

260mm x 220mm

I/O Options

32-bit VESA local bus slots (3)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Turbo switch

H1

Reset switch

H5

Turbo LED

H2

External battery

J1

Power LED & keylock

H3

32-bit VESA local bus slots

SL1 - SL3

Speaker

H4

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

Turbo enabled

H1

Closed

 

Turbo enabled through keyboard (CTRL, ALT, +)

H1

Open

 

Turbo disabled through keyboard (CTRL, ALT, -)

H1

Open

CMOS memory normal operation

J1

Pins 2 & 3 closed

 

CMOS memory clear

J1

Pins 3 & 4 closed

 

Battery type select external

J1

Closed

Monitor type select color

J3

Closed

 

Monitor type select monochrome

J3

Open

VL-BUS clock normal operation

JP43

Pins 2 & 3 closed

 

VL-BUS clock adjusted

JP43

Pins 1 & 2 closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

1MB

(4) 256K x 9

None

2MB

(4) 256K x 9

(4) 256K x 9

4MB

(4) 1M x 9

None

5MB

(4) 256K x 9

(4) 1M x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

None

20MB

(4) 1M x 9

(4) 4M x 9

20MB

(4) 4M x 9

(4) 1M x 9

32MB

(4) 4M x 9

(4) 4M x 9

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

128KB

(4) 32K x 8

None

(1) 8K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

CACHE JUMPER CONFIGURATION

Size

JP6

JP7

JP8

JP9

64KB

Open

Closed

Open

Pins 1 & 2 closed

128KB

Open

Closed

Closed

Pins 1 & 2, 3 & 4 closed

256KB

Closed

Closed

Closed

Pins 1 & 2, 4 & 5 closed

CPU SPEED SELECTION

Speed

JP29

JP30

JP31

20MHz

Open

Closed

Open

25MHz

Closed

Open

Closed

33MHz

Closed

Closed

Open

50iMHz

Closed

Open

Closed

50MHz

Open

Closed

Open

66iMHz

Closed

Closed

Open

CPU TYPE SELECTION

Type

JP4

80486SX

Pins 5 & 6 closed

80486DX

Pins 1 & 2, 4 & 5, 6 & 7 closed

80486DX2

Pins 1 & 2, 4 & 5, 6 & 7 closed

VL BUS WAIT STATE SELECTION

Setting

JP20

 

0

Open

1

Closed

VL BUS SPEED SELECTION

Speed

JP19

 

<= 33MHz

Open

>33 MHz

Closed