J-MARK COMPUTER CORPORATION

JET-486DX/SX 20/25 NON-CACHE

Processor

80486SX/80486DX

Processor Speed

20/25/33MHz

Chip Set

ETEQ

Max. Onboard DRAM

32MB

Cache

None

BIOS

AMI

Dimensions

220mm x 220mm

I/O Options

None

NPU Options

80487SX

CONNECTIONS

Purpose

Location

Purpose

Location

Reset switch

J1

Turbo switch

J4

Power LED & keylock

J2

External battery

JP1

Speaker

J3

Turbo LED

JP5

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Monitor type select color

JP2

Closed

 

Monitor type select monochrome

JP2

Open

»

CMOS memory normal operation

JP3

Closed

 

CMOS memory clear

JP3

Open

»

Factory configured - do not alter

JP12

Closed

»

Oscillator speed select 25MHz

JP13

pins 1 & 2 closed

 

Oscillator speed select 20MHz

JP13

pins 2 & 3 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) 1 M x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

32MB

(4) 4M x 9

(4) 4M x 9

CPU TYPE CONFIGURATION

Type

JP8

JP9

JP10

JP11

80486SX

Open

Open

pins 1 & 2 closed

pins 1 & 2 closed

80487SX

Closed

Open

Open

pins 2 & 3 closed

80486DX

Closed

Closed

pins 2 & 3 closed

pins 1 & 2 closed

CHIPSET TYPE CONFIGURATION

Type

JP6

JP7

JP14

JP15

82C493

pins 1 & 2 closed

pins 2 & 3 closed

pins 2 & 3 closed

pins 1 & 2 closed

82C492

pins 2 & 3 closed

pins 1 & 2 closed

pins 1 & 2 closed

pins 2 & 3 closed