HwMuseum | Index

DIGITAL EQUIPMENT CORPORATION

DECPC LP

Device Type

Mainboard

Processor

80486SX/80486DX/80486DX2

Processor Speed

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

Chip Set

OPTI

Video Chip Set

Unidentified

Maximum Onboard Memory

64MB

Maximum Video Memory

1MB

Cache

64KB

BIOS

Unidentified

Dimensions

254mm x 218mm

I/O Options

Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA feature connector, VGA port, riser slot

NPU Options

None

CONNECTIONS

Purpose

Location

Purpose

Location

VGA port

CN1

IDE interface

CN6

Parallel port

CN2

Floppy drive interface

CN7

Serial port 2

CN3

VGA feature connector

CN8

Serial port 1

CN4

CPU board connectors

CN9

PS/2 mouse port

CN5

Riser slot

SL1

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

VGA IRQ9 disabled

J1

Open

 

VGA IRQ9 enabled

J1

Closed

»

On board video disabled

J2

Open

 

On board video enabled

J2

Closed

»

CMOS memory normal operation

J3

Pins 1 & 2 closed

 

CMOS memory clear

J3

Pins 2 & 3 closed

 

Reset switch enabled

J4

Closed

 

Reset switch disabled

J4

Open

 

Parallel port unidirectional

J5

Pins 1 & 2 closed

 

Parallel port bidirectional

J5

Pins 2 & 3 closed

»

Factory configured - do not alter

J10

Open

»

Monitor type select color

J11

Closed

 

Monitor type select monochrome

J11

Open

»

Factory configured - do not alter

J29

Open

»

Factory configured - do not alter

J30

Open

»

Factory configured - do not alter

J31

Open

 

VGAIOW select local

J35

Pins 1 & 2 closed

 

VGAIOW select local & ISA

J35

Pins 2 & 3 closed

SIMM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

4MB

(1) 1M x 36

None

None

None

8MB

(1) 2M x 36

None

None

None

8MB

(1) 1M x 36

(1) 1M x 36

None

None

12MB

(1) 2M x 36

(1) 1M x 36

None

None

12MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

None

SIMM CONFIGURATION (CON’T)

Size

Bank 0

Bank 1

Bank 2

Bank 3

12MB

(1) 1M x 36

(1) 2M x 36

None

None

16MB

(1) 4M x 36

None

None

None

16MB

(1) 2M x 36

(1) 1M x 36

(1) 1M x 36

None

16MB

(1) 2M x 36

(1) 2M x 36

None

None

16MB

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

20MB

(1) 4M x 36

(1) 1M x 36

None

None

20MB

(1) 2M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

20MB

(1) 1M x 36

(1) 2M x 36

(1) 2M x 36

None

20MB

(1) 1M x 36

(1) 4M x 36

None

None

24MB

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

None

24MB

(1) 4M x 36

(1) 2M x 36

None

None

24MB

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

None

24MB

(1) 2M x 36

(1) 4M x 36

None

None

28MB

(1) 4M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

32MB

(1) 8M x 36

None

None

None

32MB

(1) 4M x 36

(1) 4M x 36

None

None

32MB

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

36MB

(1) 8M x 36

(1) 1M x 36

None

None

40MB

(1) 8M x 36

(1) 1M x 36

(1) 1M x 36

None

40MB

(1) 8M x 36

(1) 2M x 36

None

None

40MB

(1) 4M x 36

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

40MB

(1) 2M x 36

(1) 4M x 36

(1) 4M x 36

None

40MB

(1) 2M x 36

(1) 8M x 36

None

None

44MB

(1) 8M x 36

(1) 1M x 36

(1) 1M x 36

(1) 1M x 36

48MB

(1) 8M x 36

(1) 2M x 36

(1) 2M x 36

None

48MB

(1) 8M x 36

(1) 4M x 36

None

None

48MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

None

48MB

(1) 4M x 36

(1) 8M x 36

None

None

56MB

(1) 8M x 36

(1) 2M x 36

(1) 2M x 36

(1) 2M x 36

56MB

(1) 2M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

64MB

(1) 8M x 36

(1) 4M x 36

(1) 4M x 36

None

64MB

(1) 8M x 36

(1) 8M x 36

None

None

64MB

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

(1) 4M x 36

VIDEO MEMORY CONFIGURATION

Note: Board accepts 512KB/1MB of video memory. The configuration is unidentified.

VIDEO MEMORY JUMPER CONFIGURATION

Size

J28

512KB

Pins 1 & 2 closed

1MB

Pins 2 & 3 closed

CONNECTIONS

Purpose

Location

CPU board connectors

CN9

CACHE CONFIGURATION

Size

Bank 0

128KB

(4) 32K x 8

256KB

(4) 64K x 8

CACHE JUMPER CONFIGURATION

Size

J103

J104

128KB

Pins 1 & 2 closed

Pins 1 & 2 closed

256KB

Pins 2 & 3 closed

Pins 2 & 3 closed

CPU SPEED SELECTION

Speed

J109

J110

J111

J112

33MHz

Closed

Open

Open

Open

66iMHz

Closed

Open

Open

Open

CPU TYPE SELECTION

Type

J114

J115

80486SX

Pins 2 & 3 closed

Pins 2 & 3 closed

80486DX

Pins 1 & 2 closed

Pins 1 & 2 closed

CPU SECOND SOCKET SELECTION

Setting

J101

J102

J103

Not installed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

ODP486

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

80486DX

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed

80486DX2

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed

CONNECTIONS

Purpose

Location

CPU board connectors

CN9

CACHE CONFIGURATION

Size

Bank 0

128KB

(4) 32K x 8

256KB

(4) 64K x 8

CACHE JUMPER CONFIGURATION

Size

J103

J104

128KB

Pins 1 & 2 closed

Pins 1 & 2 closed

256KB

Pins 2 & 3 closed

Pins 2 & 3 closed

CPU SPEED SELECTION

Speed

J109

J110

J111

J112

25MHz

Closed

Open

Open

Open

50iMHz

Closed

Open

Open

Open

CPU SECOND SOCKET SELECTION

Setting

J101

J102

J103

Not installed

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

ODP486

Pins 1 & 2 closed

Pins 1 & 2 closed

Pins 1 & 2 closed

80486DX

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed

80486DX2

Pins 2 & 3 closed

Pins 2 & 3 closed

Pins 2 & 3 closed