420SXB/425SXB/433SCB/450SCB Motherboard Settings and Configuration

Processor	80486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed	16/20/25/33/50(internal)/50/66(internal)MHz
Chip Set	SIS
Max. Onboard DRAM	32MB
Cache	64/128/256KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	None
NPU Options	4167

CONNECTIONS
Purpose	Location	Purpose	Location
External battery	J1	Speaker	J4
Turbo LED	J2	Power LED & keylock	J5
Turbo switch	J3	Reset switch	J6

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Turbo enabled	J3	Closed
	Turbo disabled	J3	Open
»	Monitor type select monochrome	J7	Open
	Monitor type select color	J7	Closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1
1MB	(4) 256K x 9	NONE
2MB	(4) 256K x 9	(4) 256K x 9
4MB	(4) 1M x 9	NONE
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

CACHE CONFIGURATION
Size	Bank 0	Bank 1	TAG
64KB	(4) 8K x 8	(4) 8K x 8	(1) 8K x 8
128KB	(4) 32K x 8	NONE	(1) 8K x 8
256KB	(4) 32K x 8	(4) 32K x 8	(1) 32K x 8

CACHE JUMPER CONFIGURATION
Size	RN12	RN15	RN16	RN17	RN18	RN19
64KB	Installed	Installed	Not installed	Not installed	Not installed	Not installed
128KB	Not installed	Not installed	Not installed	Installed	Installed	Not installed
256KB	Not installed	Not installed	Installed	Not installed	Not installed	Installed

CPU TYPE CONFIGURATION
Type	JP7
80486SX	pins 2 & 3 closed
ODP486SX	pins 2 & 3 closed
80487SX	pins 2 & 3 closed
80486DX	pins 1 & 2 closed
80486DX2	pins 1 & 2 closed

CPU SPEED CONFIGURATION
Speed	JP1
16MHz	pins 2 & 3 closed
20MHz	pins 2 & 3 closed
> 25MHz	pins 1 & 2 closed

MISCELLANEOUS TECHNICAL NOTE

Note:If a Weitek coprocessor is desired, the optional daughter board must be installed in CPU socket.