TANDY/RADIO SHACK

4025 LX (250-5125), 4033 LX

Processor

80386

Processor Speed

25MHz

Chip Set

Unidentified

Video Chip Set

None

Maximum Onboard Memory

16MB (on external memory cards)

Maximum Video Memory

None

Cache

32KB

BIOS

Unidentified

Dimensions

355mm x 304mm

I/O Options

External memory cards (2) CPU slot, floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial port

NPU Options

80387/3167

CONNECTIONS

Purpose

Location

Purpose

Location

PS/2 mouse port

CN1

External battery

CN6

Serial port

CN2

Speaker

CN7

Parallel port

CN3

External memory cards

SL1 & SL2

IDE interface

CN4

CPU slot

SL3

Floppy drive interface

CN5

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

Monitor type select through software

J1

Pins 2 & 3 closed

 

Monitor type select color

J1

Pins 1 & 2 closed

 

Monitor type select monochrome

J1

Open

»

IDE IOCHRDY enabled

J4

Closed

 

IDE IOCHRDY disabled

J4

Open

»

IDE DIAG normal operation

J5

Open

 

IDE DIAG diagnostic mode

J5

Closed

»

I/O recovery mode enabled

J6

Closed

 

I/O recovery mode disabled

J6

Open

»

Factory configured - do not alter

J7

Closed

»

Factory configured - do not alter

J8

Closed

»

Factory configured - do not alter

J9

Closed

DRAM CONFIGURATION

Size

Bank 0

Bank 1

Bank 2

Bank 3

1MB

(4) 256K x 9

None

None

None

2MB

(4) 256K x 9

(4) 256K x 9

None

None

4MB

(4) 1M x 9

None

None

None

8MB

(4) 1M x 9

(4) 1M x 9

None

None

4MB

(4) 256K x 9

(4) 256K x 9

(4) 256K x 9

(4) 256K x 9

10MB

(4) 1M x 9

(4) 1M x 9

(4) 256K x 9

(4) 256K x 9

16MB

(4) 1M x 9

(4) 1M x 9

(4) 1M x 9

(4) 1M x 9

Note: Banks 0 & 1 are located on the first memory card and banks 2 & 3 are located on the second memory card.

CACHE CONFIGURATION

Note: The location of the 32KB cache is unidentified.

BIOS SELECTION

Setting

J2

J3

 

27128

Open

Open

»

27256

Closed

Closed

 

27512

Open

Closed

MISCELLANEOUS TECHNICAL NOTE

Jumpers are labeled for information and location purposes only. The purpose of SL4 is unidentified.