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EPSON Equity 4SX/25, 4DX/33, and 4DX2/50
Jumper Settings
J7
J5
,J13
J15
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
JlO,
J11, and J12 are set correctly.
Processor Speed Jumper
Settirzgs
Processor type
J19
520
521
J22
SXI25,
DX2150
Off
Off On
Off
(25 MHz)
DXI33,
DX2/66
On
Off Off Off
(33 MHz)
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
Adapter, CMOS, and PQFP Jumper Settings
System
OverDrive
processor
4SW25
ODP486-25
4DXl33 ODP486-33
Jumper
number
J5”’
J6
JT”*
J8
Jumper
setting
On
Off’
l-2’
2-3
On
Off’
l-2’
Function
Supports CGA adapters
Supports monochrome, EGA, MCGA, and
VGA adapters
Enabtes
the built-in VGA display adapter
Disables the built-in VGA display adapter so
you can use a disphy adapter on an option
card in the computer as the primary adapter
Returns CMOS RAM to the factory settings
Retains SETUP program settings
Reserved
1
J18
1
Gate A20 reset (standard setting for windows)
I
J23”
2-3
Keyboard reset
1-2
Enables the WFP SW25 processor
12-3
l
Factory setting
**
1
DisaMes
the PQFP
SX/25
processor
Factory setting depends on type of processor on system board
l
** Two pin jumpers
Processor Jumper Settings
Processor type
486SX
(in
OverDrive
socket)
487SX (in OverDrive socket)
1
or 486SX PQFP
JlO
2-3
l-2
Jll
J12
2-3
Off
1-2
2-3
I
I
I
I
I I I
486DX
(in
OverDrive
socket)
1
1-2
1
1-2
1
1-2
1
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.
SIMM lnstallation
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
1
Total memory
SiMM
0
SIMM
1
4MB
14MB’
i AMR
i
AMR
I
. . ..-
. . ..-
B
1
1MB
I5MB
B
4MB
5MB
B
4MB
8MB
16MB
t
4Mi
16L
4MB
20MB
B
16MB
20MB
1B
16MB
32MB
*
Standard memory
EPSON Equity-6
4/1/93