J-BOND COMPUTER SYSTEMS CORPORATION

486 VL450C-1

Processor

80486SX/80486DX/80486DX2

Processor Speed

20/25/33/40(internal)/50(internal)/50/66(internal)MHz

Chip Set

SIS

Max. Onboard DRAM

32MB

Cache

64/128/256KB

BIOS

AMI

Dimensions

230mm x 218mm

I/O Options

32-bit VESA local bus slots (2)

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

External battery

J1

Turbo LED

J5

Power LED & keylock

J2

Reset switch

J6

Speaker

J3

32-bit VESA Local bus slots

SL1 & SL2

Turbo switch

J4

   

USER CONFIGURABLE SETTINGS

Function

Jumper

Position

»

Factory configured - do not alter

J7

Open

»

A20 type select fast gate

JP2

pins 1 & 2 closed

 

A20 type select keyboard controller gate

JP2

pins 2 & 3 closed

»

CMOS memory normal operation

JP3

Open

 

CMOS memory clear

JP3

pins 2 & 3 closed

»

VESA local bus normal operation

JP27

pins 1 & 2 closed

 

VESA local bus compatibility problems (See note below)

JP27

pins 2 & 3 closed

»

PQFP CPU enabled

JSX6

Open

 

PQFP CPU disabled

JSX6

Closed

Note: If compatibility problems arise with nonstandard VESA local bus peripherals, jumper pins 2 & 3.

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

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

20MB

(4) 1M x 9

(4) 4M 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 or (1) 32K x 8

128KB

(4) 32K x 8

NONE

(1) 8K x 8 or (1) 32K x 8

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

CACHE JUMPER CONFIGURATION

Size

JP4

JP5

JP6

JP7

64KB

Open

Open

Open

Open

128KB

Closed

pins 1 & 2 closed

Open

Closed

256KB

Closed

pins 2 & 3 closed

Closed

Closed

CPU TYPE CONFIGURATION

Type

JSX1

JSX2

JSX3

JSX4

JSX5

80486SX

Open

Open

Open

Closed

Open

80487SX

Open

Closed

Closed

Open

Closed

80486DX/DX2

Closed

Open

Closed

Open

Closed

Overdrive

Open

Closed

Closed

Open

Closed

CPU SPEED CONFIGURATION

Speed

JP20

JP21

JP22

20MHz

Open

Open

Open

25MHz

Closed

Open

Open

33MHz

Closed

Closed

Closed

40MHz

Closed

Closed

Open

50iMHz

Closed

Open

Open

50MHz

Open

Open

Closed

66iMHz

Closed

Closed

Closed

VESA WAIT STATE/BUS SPEED CONFIGURATION

CPU speed

Wait states

JP8

JP9

JP10

JP11

< 33MHz

0 wait states

Open

Open

Open

Open

> 33MHz

1 wait state

Short

Short

Short

Short