Dell Precision T3400 User's Guide - Page 145

3 Disconnect all telephone or network cables from the computer. NOTICE: To avoid damaging the system board, you must remove the main battery before you service the computer. 4 Disconnect your computer and all attached devices from their electrical outlets. 5 Press the power button to ground the system board. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before opening the display. NOTICE: Before touching anything inside your computer, ground yourself by touching an unpainted metal surface, such as the metal at the back of the computer. While you work, periodically touch an unpainted metal surface to dissipate static electricity, which could harm internal components. Removing the Computer Cover CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide. CAUTION: To guard against electrical shock, always unplug your computer from the electrical outlet before removing the cover. 1 Follow the procedures in "Before You Begin" on page 143. NOTE: Ensure that sufficient space exists to support the removed cover. 2 Remove the security cable from the security cable slot (if installed). 3 Lay your computer on its side with the computer cover facing up. 4 Pull back on the cover release latch. 5 With the cover release latch pulled back, lift the top of the cover up and away from the computer. 6 Slide the cover forward to remove it from the hinge slots, then set the cover aside in a secure and protected location. Adding and Replacing Parts 145