4. Check inside the server for any obvious unsafe conditions, such as metal filings, contamination, water orother liquid, or signs of fire or smoke damage.5. Check for worn, frayed, or pinched cables.6. Make sure that the power-supply cover fasteners (screws or rivets) have not been removed or tamperedwith.System reliability guidelinesReview the system reliability guidelines to ensure proper system cooling and reliability.Make sure the following requirements are met:• When the server comes with redundant power, a power supply must be installed in each power-supplybay.• Adequate space around the server must be spared to allow server cooling system to work properly. Leaveapproximately 50 mm (2.0 in.) of open space around the front and rear of the server. Do not place anyobject in front of the fans.• For proper cooling and airflow, refit the server cover before you turn the power on. Do not operate theserver for more than 30 minutes with the server cover removed, for it might damage server components.• Cabling instructions that come with optional components must be followed.• A failed fan must be replaced within 48 hours after malfunction.• A removed hot-swap fan must be replaced within 30 seconds after removal.• A removed hot-swap drive must be replaced within two minutes after removal.• A removed hot-swap power supply must be replaced within two minutes after removal.• Every air baffle that comes with the server must be installed when the server starts (some servers mightcome with more than one air baffle). Operating the server with a missing air baffle might damage theprocessor.• All processor sockets must contain either a socket cover or a processor with heat sink.• When more than one processor is installed, fan population rules for each server must be strictly followed.Working inside the server with the power onYou might need to keep the power on with the server cover removed to look at system information on thedisplay panel or to replace hot-swap components. Review these guidelines before doing so.Attention: The server might stop and data loss might occur when internal server components are exposedto static electricity. To avoid this potential problem, always use an electrostatic-discharge wrist strap or othergrounding systems when working inside the server with the power on.• Avoid loose-fitting clothing, particularly around your forearms. Button or roll up long sleeves beforeworking inside the server.• Prevent your necktie, scarf, badge rope, or hair from dangling into the server.• Remove jewelry, such as bracelets, necklaces, rings, cuff links, and wrist watches.• Remove items from your shirt pocket, such as pens and pencils, in case they fall into the server as youlean over it.• Avoid dropping any metallic objects, such as paper clips, hairpins, and screws, into the server.Handling static-sensitive devicesReview these guidelines before you handle static-sensitive devices to reduce the possibility of damage fromelectrostatic discharge.Chapter 4. Hardware replacement procedures 85