TANDY/RADIO SHACK

4825 SX

Processor

80486SX/80487SX/80486DX/80486DX2

Processor Speed

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

Chip Set

Unidentified

Video Chip Set

Unidentified

Maximum Onboard Memory

32MB

Maximum Video Memory

1MB

Cache

None

BIOS

Unidentified

Dimensions

394mm x 381mm

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

CN8

PS/2 mouse port

CN2

External battery

J1

Parallel port

CN3

Speaker

J2

Serial port 2

CN4

Reset switch

J3

Serial port 1

CN5

Power LED

J4

VGA feature connector

CN6

Riser slot

SL1

Floppy drive interface

CN7

   

USER CONFIGURABLE SETTINGS

Function

Label

Position

»

CMOS memory normal operation

JP1

Open

 

CMOS memory clear

JP1

Closed

»

Monitor frequency select 31KHz

SW1/5

Off

 

Monitor frequency select 40KHz

SW1/5

On

»

Monitor type select color

SW2/3

Off

 

Monitor type select monochrome

SW2/3

On

DRAM CONFIGURATION

Size

Bank 0

Bank 1

4MB

(4) 1M x 9

None

5MB

(4) 1M x 9

(4) 256K x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

None

20MB

(4) 1M x 9

(4) 4M x 9

32MB

(4) 4M x 9

(4) 4M x 9

VIDEO MEMORY CONFIGURATION

Size

Bank 0

Bank 1

512KB

512KB

None

1MB

512KB

512KB

Note: The location of banks 0 & 1 are unidentified. The size of the video memory chips are unidentified.

VIDEO MEMORY SWITCH CONFIGURATION

Size

SW1/6

512KB

On

1MB

Off

CPU TYPE SELECTION

Type

SW2/1

SW2/2

80486SX

Off

Off

80487SX

On

Off

80486DX

Off

Off

80486DX2

Off

Off

VIDEO RESOLUTION SELECTION (800 X 600)

Frequency

SW1/1

SW1/2

»

56Hz

Off

Off

 

60Hz

Off

On

 

72Hz

On

Off

 

56Hz

On

On

VIDEO RESOLUTION SELECTION (1024 X 768)

Frequency

SW1/3

SW1/4

»

Interlaced

Off

Off

 

60HZ non-interlaced

Off

On

 

70HZ non-interlaced

On

Off

 

Interlaced

On

On

ON BOARD VIDEO SELECTION

Setting

SW1/7

SW1/8

»

Enabled

On

Off

 

Disabled

Off

On