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Service Hints & Tips

Document ID: RMIE-3HSC9G

This document is provided to IBM and our Business Partners to help sell and/or service IBM products. It is not to be distributed beyond that audience or used for any other purpose.

CrossBrand - 486SX Jumper Settings

Applicable to: World-Wide

486SX
The 486SX is basically just a 486DX without the built-in coprocessor. It differs from a 386SX by a aster internal architecture, and with full 32-bit address and data buses. There is the co-processor socket on the board that can be populated with a co-processor (487SX) or a P23T - which is basically the same as a DX-2.
The internal cache is 8K

Intel OverDrive
The Intel OverDrive processor can be used on the 486sx-20Mhz models to 'double' the clock speed of the processor. The OverDrive will also add a math coprocessor to your system.
Upgrades for the 486 PS/1 Systems are as follows:

486SX-20 Machine has a socket for the Math Co-Processor / Upgrade.

Math Co-Processor 80487SX-20 -------> 389.95 *
Upgrade (Overdrive) ODP486-SX20 ----> 379.95 *

486SX-25 Machine also has a socket for Math Co-Processor / Upgrade.
(appearing soon..)

Upgrade (Overdrive) ODP486-SX25 ----> 499.95 *

JUMPER INFORMATION ADDED ON FEB 5, 1993

PS/1 Jumper Settings (486SX / 486DX)

486SX - 20/25

Shorted Open Comments Default

JP1 Enabled Disabled Video MEMCS16 Shorted
JP3 Normal CLK/2 Turbo Clock Control Open
JP7 Reset Run Hardware Reset Switch Open
JP9 Color Mono Color / Mono Monitor Shorted
JP14 ------- -------- Reserved for Future Use
JP16 Enabled Disabled Parity Check Enable Shorted
JP17 Enabled Disabled Video Int9 Enable Open (1)
JP23 486SX 486DX BIOS Processor Type Shorted
JP24 Enabled Disabled PS/2 Mouse Interrupt Shorted
JP26 1-2 Beeper Speaker Beeper / Speaker Shorted (2)

1-2 3 1 2-3
JP8 Internal External Int / Ext Battery 1-2
JP10 Disabled Enabled On-Board VGA Enable 2-3
JP15 -------- ------- Reserved for Future Use

486DX - 33

Shorted Open Comments Default
JP3 Normal CLK/2 Turbo Clock Control Open
JP3 Normal CLK/2 Turbo Clock Control Open
JP4 27512 EPROM 27256 EPROM EPROM Type Shorted
JP7 Reset Run Hardware Reset Switch Open
JP9 Color Mono Color / Mono Monitor Shorted
JP16 Enabled Disabled Parity Check Enable Shorted
JP17 Enabled Disabled Video MEMCS16 Shorted
JP20 1-2 Beeper Speaker Beeper / Speaker Shorted (2)
JP206 128K > 128K CACHE Size Control Shorted
JP208 486SX 486DX BIOS Processor Type Open
JP209 Enabled Disabled PS/2 Mouse Interrupt Shorted
JP305 Enabled Disabled Video Int9 Enable Open (1)
The above jumper should be removed if using 3278/3279 emulator card.

-2 3 1 2-3
JP8 Internal External Int / Ext Battery 1-2
JP10 Disabled Enabled On-Board VGA Enable 2-3
JP200 Direct 2-Way CACHE Mapping Control 1-2
JP201 Direct 2-Way CACHE Mapping Control 1-2
JP207 (3) (3) CACHE RAM Control 1-2
JP304 Disabled Enabled Video BIOS Enable ????????

Note(1): Some planars were shipped with this jumper SHORTED. This could
cause contention with 3270 Emulator or IBM Token Ring LAN
Adapter or any card needing to use IRQ9.
Cards shipped with this OPEN will have the jumper on only one
pin.

(2): Speaker is connected via a 4 pin single row connector. The beeper
is enabled by SHORTing pins 1 and 2.

(3): Cache RAM is soldered and cannot be changed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Search Keywords

Hint Category

Processors

Date Created

08-08-95

Last Updated

22-01-99

Revision Date

10-08-99

Brand

Cross Brand

Product Family

Various

Machine Type

Various

Model

TypeModel

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