...because we can't all be on the bleeding edge...





TURBO MAINBOARD

UNIDENTIFIED

TURBO MAINBOARD

Processor

8088

Processor Speed

4.77/8MHz

Chip Set

Unidentified

Video Chip Set

None

Maximum Onboard Memory

640KB

Maximum Video Memory

None

Cache

None

BIOS

Unidentified

Dimensions

330mm x 218mm

I/O Options

None

NPU Options

8087

CONNECTIONS

Purpose

Location

Purpose

Location

Operating mode interface

P3

Keyboard connector

P5

Speaker

P4

Reset switch

SW2

USER CONFIGURABLE SETTINGS

Function

Label

Position

 

I/O address is C0H (bit 0 low = turbo mode; high = normal mode)

E1

Pins 1 & 2 closed

 

I/O address is 061H (bit 2 low = turbo mode; high = normal mode)

E1

Pins 2 & 3 closed

 

CPU changes speed during disk drive access

E6

Closed

 

CPU does not change speed during disk drive access

E6

Open

 

Boot memory test enabled

SW1/1

On

 

Boot memory test disabled

SW1/1

Off

 

NPU not installed

SW1/2

On

 

NPU installed

SW1/2

Off

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

64KB

(9) 4164

None

None

None

128KB

(9) 4164

(9) 4164

None

None

192KB

(9) 4164

(9) 4164

(9) 4164

None

256KB

(9) 4164

(9) 4164

(9) 4164

(9) 4164

256KB

(9) 41256

None

None

None

512KB

(9) 41256

(9) 41256

None

None

576KB

(9) 41256

(9) 41256

(9) 4164

None

640KB

(9) 41256

(9) 41256

(9) 4164

(9) 4164

DRAM JUMPER/SWITCH CONFIGURATION

Size

E4

SW1/3

SW1/4

64KB

Open

On

On

128KB

Open

Off

On

192KB

Open

On

Off

256KB

Open

Off

Off

256KB

Closed

On

On

512KB

Closed

Off

On

576KB

Closed

On

Off

640KB

Closed

Off

Off

FLOPPY DRIVE SELECTION

Drives installed

SW1/7

SW1/8

1

On

On

2

On

Off

3

Off

On

4

Off

Off

MONITOR SELECTION

Type

SW1/5

SW1/6

None

On

On

Color (80 x 25)

On

Off

Color (40 x 25)

Off

On

Monochrome

Off

Off

ROM SELECTION

U25 address

U26 address

E2

E3

F6000H - FDFFFH

FE000H - FFFFFH

Closed

Closed

F4000H - FBFFFH

FC0000H - FFFFFH

Closed

Open

F0000H - F7FFFH

F8000H - FFFFFH

Open

Open