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





425SX/T, 433SX/T, 433DX/T, 450DX2/T, 466DX2/T

TANDY/RADIO SHACK

425SX/T, 433SX/T, 433DX/T, 450DX2/T, 466DX2/T

Processor

80486SX/ODP486SX/80487SX/80486DX/ODP486SX/80486DX2

Processor Speed

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

Chip Set

Unidentified

Video Chip Set

Unidentified

Maximum Onboard Memory

40MB

Maximum Video Memory

1MB

Cache

64/128/256KB

BIOS

Phoenix

Dimensions

330mm 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

Reset switch

CN8

Parallel port

CN2

External battery

J7

Serial port 1

CN3

IDE interface

J17

Serial port 2

CN4

Floppy drive interface

J18

PS/2 mouse port

CN5

VGA feature connector

J21

IDE interface LED

CN6

Riser slot

SL1

Power LED & keylock

CN7

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Factory configured - do not alter

J9

Pins 1 & 2 closed

»

Factory configured - do not alter

J11

Open

»

Factory configured - do not alter

J13

Pins 1 & 2 closed

»

Factory configured - do not alter

J14

Pins 2 & 3 closed

»

CMOS memory normal operation

J20

Closed

 

CMOS memory clear

J20

Open

»

On board video enabled

J28

Pins 2 & 3 closed

 

On board video disabled

J28

Pins 1 & 2 closed

»

Factory configured - do not alter

J29

Open

»

Floppy drive write protect disabled

J30

Pins 2 & 3 closed

 

Floppy drive write protect enabled

J30

Pins 1 & 2 closed

»

Factory configured - do not alter

J31

Pins 2 & 3 closed

»

Zero wait state enabled

J32

Closed

 

Zero wait state disabled

J32

Open

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

1MB

(1) 256K x 36

None

None

2MB

None

(4) 256K x 9

(4) 256K x 9

2MB

(1) 512K x 36

None

None

4MB

None

(4) 1M x 9

None

4MB

(1) 1M x 36

None

None

5MB

None

(4) 1M x 9

(4) 256K x 9

6MB

(1) 512K x 36

(4) 1M x 9

None

8MB

(1) 1M x 36

(4) 1M x 9

None

8MB

(1) 2M x 36

None

None

8MB

None

(4) 1M x 9

(4) 1M x 9

10MB

(1) 512K x 36

(4) 1M x 9

(4) 1M x 9

12MB

(1) 1M x 36

(4) 1M x 9

(4) 1M x 9

12MB

(1) 2M x 36

(4) 1M x 9

None

16MB

(1) 2M x 36

(4) 1M x 9

(4) 1M x 9

16MB

None

(4) 4M x 9

None

DRAM CONFIGURATION (CON’T)

Size

Bank 0

Bank 1

Bank 2

17MB

None

(4) 4M x 9

(4) 256K x 9

18MB

(1) 512K x 36

(4) 4M x 9

None

20MB

(1) 1M x 36

(4) 4M x 9

None

20MB

None

(4) 4M x 9

(4) 1M x 9

22MB

(1) 512K x 36

(4) 4M x 9

(4) 1M x 9

24MB

(1) 1M x 36

(4) 4M x 9

(4) 1M x 9

24MB

(1) 2M x 36

(4) 4M x 9

None

28MB

(1) 2M x 36

(4) 4M x 9

(4) 1M x 9

32MB

None

(4) 4M x 9

(4) 4M x 9

34MB

(1) 512K x 36

(4) 4M x 9

(4) 4M x 9

36MB

(1) 1M x 36

(4) 4M x 9

(4) 4M x 9

40MB

(1) 2M x 36

(4) 4M x 9

(4) 4M x 9

CACHE CONFIGURATION

Size

Bank 0

Bank 1

TAG

U1

64KB

(4) 8K x 8

(4) 8K x 8

(1) 8K x 8

(1) 64K x 1

128KB

(4) 32K x 8

None

(1) 8K/32K x 8

(1) 64K x 1

256KB

(4) 32K x 8

(4) 32K x 8

(1) 32K x 8

(1) 64K x 1

CACHE JUMPER CONFIGURATION

Size

J16

None

Pins 1 & 2, 3 & 4, 5 & 6, 9 & 10 closed

64KB

Open

128KB

Pins 1 & 2, 5 & 6, 7 & 8 closed

256KB

Pins 1 & 2, 3 & 4, 5 & 6, 9 & 10 closed

VIDEO MEMORY CONFIGURATION

Size

Bank 0

Bank 1

512KB

512KB

None

1MB

512KB

512KB

Note: The size of the video memory chips are unidentified.

CPU SPEED SELECTION

Speed

J26

J27

25MHz

Pins 1 & 2 closed

Pins 2 & 3 closed

33MHz

Pins 1 & 2 closed

Pins 1 & 2 closed

50iMHz

Pins 1 & 2 closed

Pins 2 & 3 closed

66iMHz

Pins 1 & 2 closed

Pins 1 & 2 closed

CPU TYPE SELECTION

Type

J19

80486SX

Pins 1 & 3, 2 & 4 closed

ODP486SX

Pins 1 & 3, 2 & 4 closed

80487SX

Pins 1 & 3, 2 & 4 closed

80486DX

Pins 3 & 5, 4 & 6 closed

ODP486DX

Pins 3 & 5, 4 & 6 closed

80486DX2

Pins 3 & 5, 4 & 6 closed