Positive PC425

The PC425 is an 80486 based PC compatible made by Positive Corporation.

Jumper Settings

Processor	80486SX
Processor Speed	25MHz
Chip Set	Unidentified
Max. Onboard DRAM	5MB
Cache	None
BIOS	Unidentified
Dimensions	254mm x 218mm
I/O Options	Parallel port, serial ports (2), VGA port, floppy drive interface, IDE interface, riser slot
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
Serial port 2	J2	External battery	J12
Serial port 1	J3	Power/speed indicator	J17
Parallel port	J4	VGA port	J22
Speaker	J6	Riser Card	SL1
Floppy drive interface	J10	Reset switch	SW1
IDE interface	J11

USER CONFIGURABLE SETTINGS
Function		Jumper/Switch	Position
»	Factory configured - do not alter	E1	pins 2 & 3 closed
»	IDE interface interrupt enabled	E2	pins 1 & 2 closed
	IDE interface interrupt disabled	E2	Open
»	Factory configured - do not alter	E3	pins 2 & 3 closed
»	Factory configured - do not alter	E4	pins 2 & 3 closed
»	Factory configured - do not alter	E5	pins 2 & 3 closed
»	Factory configured - do not alter	E8	pins 1 & 2 closed
»	Factory configured - do not alter	E9	pins 2 & 3 closed
»	Parity disabled	E10	pins 2 & 3 closed
	Parity enabled	E10	pins 1 & 2 closed
»	Factory configured - do not alter	E11	pins 2 & 3 closed
»	Onboard RAM 256KB to 512KB enabled	sw2/1	Off
	Onboard RAM 256KB to 512KB disabled	sw2/1	On
»	Onboard RAM 512KB to 640KB enabled	sw2/2	Off
	Onboard RAM 512KB to 640KB disabled	sw2/2	On
»	Security enabled	sw2/3	Off
	Security disabled	sw2/3	On
»	Factory configured - do not alter	sw2/4	Off

DRAM CONFIGURATION
Size	Bank 0	Bank 1
1MB	1MB	NONE
5MB	1MB	(4) 1M x 9
Note: Bank 0 is factory installed and is not configurable. The location is unidentified.

IDE CONFIGURATION
Setting	E6	E7
Primary	pins 2 & 3 closed	pins 2 & 3 closed
Secondary	pins 1 & 2 closed	pins 1 & 2 closed

Basic Input Output System

Video Graphics Array

Intergrated Drive Electronics