AMERICAN MEGATRENDS, INC.

386 AT MARK II SYSTEM MOTHERBOARD

Processor

80386

Processor Speed

16/20/25/33MHz

Chip Set

Unidentified

Video Chip Set

None

Maximum Onboard Memory

16MB (8MB on external memory card)

Maximum Video Memory

None

Cache

None

BIOS

AMI

Dimensions

355mm x 304mm

I/O Options

External memory card

NPU Options

80387/3167

CONNECTIONS

Purpose

Location

Purpose

Location

Turbo LED

J1

Power LED & keylock

J8

Reset switch

J2

External battery

J9

Speaker

J7

External memory card

SL1

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Factory configured - do not alter

J26

Unidentified

 

Factory configured - do not alter

SW/1

Off

 

Monitor type select color

SW/2

On

 

Monitor type select monochrome

SW/2

Off

DRAM CONFIGURATION

Size

Bank 0

Bank 1

1MB

(36) 41256

None

1MB

None

(4) 256K x 9

2MB

(36) 41256

(4) 256K x 9

4MB

(36) 411000

None

4MB

None

(4) 1M x 9

5MB

(36) 41256

(4) 1M x 9

5MB

(36) 411000

(4) 256K x 9

8MB

(36) 411000

(4) 1M x 9

16MB

None

(4) 4M x 9

Note: Board will accept 441000 chips but the configuration was not available.

DRAM JUMPER CONFIGURATION

Bank 0 chips

Bank 1 chips

J27

Installed

Not installed

Pins 1 & 2, 3 & 4 closed

Not installed

Installed

Pins 2 & 3, 4 & 5 closed

41256

256K/1M

Pins 1 & 2, 3 & 4 closed

411000

256K/1M

Pins 2 & 3, 4 & 5 closed

441000

Any chip type

Pins 1 & 2, 3 & 4 closed

Any chip type

4M

Pins 2 & 3, 4 & 5 closed

DRAM CONFIGURATION

Size

Bank 2

Bank 3

8MB

(18) 411000

(18) 411000

DRAM SWITCH CONFIGURATION

Mark II memory

BASE board memory

SW/1

SW/2

SW/3

640KB

1 bank

Off

On

On

896KB

2 banks

On

On

On

1664KB

1 bank

Off

Off

On

1920KB

2 banks

On

Off

On

3712KB

1 bank

Off

On

On

3968KB

2 banks

On

On

On

4736KB

1 bank

Off

On

Off

4992KB

2 banks

On

On

Off

7808KB

1 bank

Off

Off

On

8064KB

2 banks

On

Off

On

N/A*

2 banks

On

Off

Off

Note: * = Memory configuration in the 14MB & 15MB region is enabled. For all other configurations, the region is disabled.