2-10 Dell Dimension 900 System Reference and Troubleshooting Guide

Boot-Block Select Jumper

Figure 2-4 shows the location of the boot-block select jumper (JP7) in your computer.
Table 2-5 describes the settings and functions of the boot-block select jumper.
Removing and Replacing the Riser-Board Bracket
Certain system board upgrades require that you remove and replace the riser-board
bracket. To remove the riser-board bracket, perform the following steps.
CAUTION: Before you remove the computer cover, see “Safety First—For
You and Your Computer” found e arlier in this chapter.
1. Remove the computer cover according to the instructions in Removing and
Replacing the Computer Cover found earlier in this chapter.
2. Remove the riser-board screw (see Figure 2-5).
3. Hold the back of the diskette drive with one hand to prevent it from moving as
you perform step 4.
4. Slip one finger into the oval opening on top of the riser-board bracket (see
Figure2-5). Then slightly lift the back end of the riser-board bracket and gently pull
the riser-board bracket toward the back of the computer until its front tab is free
from the front chassis slot and its two side diskette-drive slots are clear of the
diskette-drive tabs.
CAUTION: When handling the riser board bracket, always hold it by plac-
ing a finger through the oval opening in the bracket (see Figure 2-5). Do
not grasp the bracket by its edges, which may be sharp.

Table 2-5. Boot-Block Jumper Settings

Jumper
Settings Description
Normal boot setting (default). Change this setting only if
instructed to by Dell Technical Support.
Boot from top block setting
NOTE: The Glossary in the system Help define s abbreviations and acronyms.