DELL COMPUTER CORPORATION

Precision 486SX/25, Precision 486DX/33

Processor

80486SX/80487SX/80486DX

Processor Speed

25/33MHz

Chip Set

OPTI

Max. Onboard DRAM

32MB

Cache

64/256KB

BIOS

AMI

Dimensions

330mm x 218mm

I/O Options

None

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

Reset switch

J9

Speaker

J21

External battery

J18

Power LED & keylock

J22

Turbo switch

J20

   

Note:Although there is a 4167 socket on the board, it is not supported. (As per the manufacturer)

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Battery select internal

W1

Closed

 

Battery select external

W1

Open

»

CMOS memory normal operation

W2

pins 1 & 2 closed

 

CMOS memory clear

W2

pins 2 & 3 closed

»

CPU speed select ATCLK/4

W3

pins 2 & 3 closed

 

CPU speed select ATCLK/6

W3

pins 1 & 2 closed

»

Factory configured - do not alter

W8

Open

»

Factory configured - do not alter

W9

Open

»

Factory configured - do not alter

W10

Open

»

Monitor type select color

W12

pins 1 & 2 closed

 

Monitor type select monochrome

W12

pins 2 & 3 closed

»

Factory test disabled

W13

Open

 

Factory test enabled

W13

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) 1M x 9

(4) 256K x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

20MB

(4) 4M x 9

(4) 256K x 9

32MB

(4) 4M x 9

(4) 1M x 9

CACHE CONFIGURATION

Size

Bank 0

64KB

(8) 8K x 8

256KB

(8) 32K x 8

CACHE JUMPER CONFIGURATION

Size

W8

W9

W18

64KB

pins 2 & 3 closed

pins 2 & 3 closed

pins 2 & 3 closed

256KB

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

CPU TYPE CONFIGURATION

Type

W5

W6

W7

80486SX

pins 2 & 3 closed

pins 2 & 3 closed

Open

80487SX

pins 1 & 2 closed

pins 1 & 2 closed

pins 1 & 2 closed

80486DX

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed