321 Studios 4DX/33, 4DX2/50, 4SX/25 Jumper Settings, Processor Chips, SIMM Installation, SIMM, OverDrive, Processors, Configurations, Processor Jumper Settings, Processor Speed Jumper Settings

EPSON Endeavor 4SX/25, 4DX/33, and 4DX2/50

Jumper Settings

J7 J5

J13

J15

Adapter, CMOS, and PQFP jumper Settings

Jumper	Jumper
number	setting	Function
J5***	On	Supports CGA adapters
	Off*	Supports monochrome, EGA, MCGA, and
		VGA adapters
J6	1-2*	Enables the built-in VGA display adapter
	2-3	Disables the built-in VGA display adapter so
		you can use a display adapter on an option
		card in the computer as the primary adapter
J7***	On	Returns CMOS RAM to the factory settings
	Off’	Retains SETUP program settings
J6	1-2*	Reserved

J18	1-2*	Gate A20 reset (standard setting for windows)
J18	1-2*	Gate A20 reset (standard setting for windows)
	2-3	Keyboard reset
J23**	1-2	Enables the WFP SX/25 processor
	2-3	Disables the PQFP SX/25 processor

*Factory setting

**Factory setting depends on type of processor on system board • ** Two pin jumpers

Processor Jumper Settings

You need to change the processor jumper settings if you install a new processor chip. The settings for J10, J11, and J12 must correspond to the type of chip installed.

If the computer’s microprocessor is a FQFP type, it is surface- mounted on the main system board. To add an OverDrive processor, install it in the empty OverDrive socket and disable the original microprocessor by setting jumper J23 to position 2-3. Also make sure J10, J11, and J12 are set correctly.

Processor Speed Jumper Settings

You need to change the processor speed jumper settings if you replace a 25 MHz processor with a 33 MHz processor.

Processor Chips

If you have the 4SX/25 or 4DX/33 system, you can install an Intel OverDrive processor on the main system board to effectively double the internal clock speed of the computer’s microprocessor. Alternatively, for the 4SX/25, you can install the 487SX/25 microprocessor with built-in math coprocessor.

OverDrive	Processors

System		OverDrive processor
4SX/25		ODP486-25
40X/33		ODP486-33

SIMM Installation

The computer comes with 4MB of memory installed in a SIMM socket. To increase the amount of memory in the computer up to 32MB, you can install 36-bit, fast-page mode SIMMs that operate at an access speed of 70ns or faster, with a capacity of 1MB, 4MB, or 16MB.

The following table shows the possible SIMM configurations; do not install memory in any other configuration. Make sure that both SIMMs operate at the same speed.

SIMM	Configurations

SIMM 0		SIMM 1	Total memory
4MB			4MB *
		4MB	4MB
4MB		1MB	5MB
1MB		4MB	5MB
4MB		4MB	8MB
16MB			16MB
		16MB	16MB
16MB		1MB	17MB
1MB		16MB	17MB
16MB		4MB	20MB
4MB		16MB	20MB
16MB		16MB	32MB

•Standard memory

EPSON Endeavor-6

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