Chapter 8. Jumper Settings, Switch Settings, and Adjustments
Chapter 8.1 Introduction
This section details the switch and jumper settings for the COMPAQ Portable,
COMPAQ PLUS, and COMPAQ PORTABLE 286 Personal Computers.
This section contains external pin assignments for the COMPAQ PORTABLE 286
Diskette/Tape Controller Board and the COMPAQ Asynchronous Communications/
Clock Board.
Also contained in this section are procedures for diskette drive speed
adjustment and video display unit adjustments.
When using the tables in this section, remember that the default settings
shown are set for the system as configured by COMPAQ.
These settings only
need to be changed when the system configuration is changed.
Any time jumpers are changed in a COMPAQ PORTABLE 286 Personal Computer, the
SETUP program must be run on the system to change the system configuration
information stored in CMOS memory.
Failure to run SETUP may result in Power
On Self Test errors.
Chapter 8.2 Compaq Portable and Compaq Plus Video Display Controller Board Jumper Settings
There are three versions of the video display controller board.
Determine
which version is installed by referencing Figure 8.2-1.
Table 8.2 lists the various combinations of jumper settings for all versions
of the COMPAQ video display controller board.
This board supports only those monitors that require positive vertical and
positive horizontal synchronization pulses.
For the locations of the video display controller board jumpers, see
Figure 8.2-1.
