Compaq Enhanced Color Graphics Board Jumper And Switch Settings; Jumper E20 - Selects 20 Mhz 80387 Coprocessor Installation; Jumper E21 - Selects System Speed At Power On; Jumper E23 - Selects Plasma Display Mode At Power On - Compaq PORTABLE 386 Maintenance And Service Manual

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E19, Pins 1 and 2
E19, Pins 2 and 3
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Table 9-7.

Jumper E20 - Selects 20 MHz 80387 Coprocessor Installation

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Jumper Setting
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E20, Pins 2 and 3
E20, Pins 1 and 2
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Table 9-8.

Jumper E21 - Selects System Speed at Power On

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Jumper Setting
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E21, Pins 1 and 2
E21, Pins 2 and 3
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Table 9-9.

Jumper E23 - Selects Plasma Display Mode at Power On

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Jumper Setting
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E23, Pins 1 and 2
E23, Pins 2 and 3
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Chapter 9.4 Compaq Enhanced Color Graphics Board Jumper and Switch Settings
COMPAQ Enhanced Color Graphics Boards have two banks of configuration
switches. Version 1 (Assy No. 000410), shown in Figure 9-2, has two
jumpers that must be set for the board to work properly with the computer
system. Version 2 (Assy No. 000471), shown in Figure 9-3, has three
jumpers.
The monitor used with either COMPAQ Enhanced Color Graphics Board determines
the correct setting for one of the jumpers and one bank of configuration
switches. The other configuration switch bank setting indicates whether the
COMPAQ Enhanced Color Graphics Board is the primary (or only) display
controller board or the secondary display controller board in the computer.
This configuration switch bank also selects the power on mode and character
format of the COMPAQ Enhanced Color Graphics Board when the computer is turned
on or restarted.
The following sections provide jumper and configuration switch locations and
instructions on how to set them.
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Fail safe timer enabled (default).
Fail safe timer disabled.
Function
Selects 20 MHz 80387 coprocessor not installed or Weitek
3167 coprocessor installed (default).
Selects 20 MHz 80387 coprocessor installed or Weitek 3167
coprocessor not installed.
Function
Selects power on in AUTO mode (20 MHz/8 MHz when accessing
diskette drive) (default).
Selects power on in HIGH mode (always 20 MHz).
Function
Selects power on with plasma display in dual (CGA) mode
(3DX, B800) (default).
Selects power on with plasma display in monochrome (MDA)
mode (3BX, B000).