Hardware and Network Troubleshooting
What to know
The exam expects a repeatable method: identify the problem and gather information (back up before changing anything), establish a theory of probable cause (question the obvious), test the theory, establish a plan of action and implement it, verify full system functionality and implement preventive measures, then document. Change one variable at a time, and escalate when the fix is beyond your scope.
Hardware symptoms: no power (check PSU, wall outlet, power button, POST), beep codes or no POST, overheating and random shutdowns (dust, fans, thermal paste), bulging capacitors, burning smells (stop immediately), grinding or clicking (failing HDD - back up first), display artifacts (GPU or cable), and S.M.A.R.T. warnings.
Network tools and their uses: ipconfig/ifconfig for address and gateway, ping for reachability, tracert/traceroute for the path, nslookup/dig for DNS, netstat for connections, arp for MAC-to-IP mapping, a cable tester for continuity and pinout, a toner probe to find a cable in a bundle, a loopback plug to test a port, and a Wi-Fi analyzer for channel and interference issues.
Traps. “No internet but local access works” points to gateway or DNS, not the NIC. Duplicate IP addresses cause intermittent connectivity and conflict messages. Intermittent wireless drops usually mean interference, channel overlap, or distance - not a failed adapter. Always verify functionality and document; a fix that is not verified and recorded is an incomplete answer.
Rule of thumb. Start at Layer 1 - cable, port, link light, power - before reconfiguring software.
Worked example. Users on one floor report slow wireless at lunch. A Wi-Fi analyzer shows three neighboring APs on channel 6: move to channel 1 or 11 and retest.