Page 2 901 Hardware and Network Troubleshooting Study Guide for the CompTIA® A+ exam

Video, Projector, and Display Issues

For this section, you should be able to troubleshoot video, projector, and display issues. You should also be able to respond to a variety of symptoms associated with this technology.

  • VGA mode: This mode is similar to Safe Mode but for display issues. The PC boots with the minimum video drivers in use, which is helpful for troubleshooting.

  • no image on screen: This can happen if there is a cabling issue, or a connection is not seated properly.

  • overheat shutdown: A shutdown of this sort could be due to problems with the video card or blocked airways for ventilation.

  • dead pixels: This issue is typically related to the hardware, or the monitor itself. Replacement of the display is usually necessary to correct it.

  • artifacts: These could be caused by problems with the adapter or video drivers.

  • color patterns incorrect: Damaged cables, or a damaged connection port on the PC, may be responsible for this malfunction.

  • dim image: This irregularity often has something to do with brightness settings on the display or with adapter issues.

  • flickering image: This happens when there are damaged cables or a damaged connection port on the PC.

  • distorted image: The system settings on your OS may be responsible for a distorted image. The refresh rate or resolution may be at fault.

  • distorted geometry: This variance could be caused by display settings, video card issues, or magnetic interference.

  • burn-in: This is caused when images stick on the screen and become permanent parts of the display. It could be caused by stuck pixels.

  • oversized images and icons: If the resolution of the monitor does not match the system settings, this can be the result.

Wired and Wireless Networks

For this section, you should be able to troubleshoot issues with wired and wireless networks in any given scenario. It is also important to use the correct tools when troubleshooting these network types.

Common Symptoms

You should be familiar with these common symptoms within a networking environment.

  • no connectivity: This could be a physical connectivity issue, such as an unplugged cable.

  • APIPA/link local address: This indicates an issue reaching the DHCP server.

  • limited connectivity: Using the APIPA address may be the cause of this.

  • local connectivity: This issue could be caused by having an APIPA address or various issues with IP address assigned.

  • intermittent connectivity: Loose cabling connections may be responsible.

  • IP conflict: IP addresses must be unique to each network. Conflicts can occur when addresses are statically assigned.

  • slow transfer speeds: An overloaded connection or router or a virus on local a PC can be the cause of these.

  • Low RF signal: Interference from other wireless devices or signal strength configuration can cause signal problems.

  • SSID not found: This message could be the result of an offline wireless access point or an SSID that’s disabled.

Hardware Tools

You should be familiar with all of the following tools used to troubleshoot and repair common network issues.

  • cable tester: This checks the continuity of the cable from end to end, and certifies it meets the correct standard.

  • loopback plug: A loopback plug simulates a live network connection at a port. It sends and receives signals back to itself for troubleshooting.

  • punchdown tools: These are used to permanently lock in the copper in wires to the metal contacts for sending or receiving signals. Types are a punch-down block or registered jack.

  • tone generator and probe: This is used to find the endpoint of a cable in a network closet and is helpful when there is poor labeling in the environment.

  • wire strippers: These are used to strip off the protective covering outside of wiring, so it can be used to create a usable cable connection.

  • crimper: This tool makes it possible to permanently secure the registered jack connector to the wiring.

  • wireless locator: Locating wireless network information, including signal strength and frequency, is possible with this tool.

Command Line Tools

You should be familiar with the following command line tools that aid in troubleshooting a networking environment.

  • PING: This command is used to test the reachability of a network endpoint.

  • IPCONFIG/IFCONFIG: These commands are used to display network adapter configuration information. The command ipconfig is used in Windows, while ifconfig is used in Apple and Linux environments.

  • TRACERT: This indicates the number of hops (routers) between two points on a network.

  • NETSTAT: A list of network statistics about current network conditions on your PC is produced by this command.

  • NBTSTAT: This lists NetBIOS statistics about current network conditions on your PC. You can also get information from other devices on the network.

  • NET: This is a Windows troubleshooting command that allows you to manage various services and network-related tasks.

  • NETDOM: This command allows management of certain aspects of Active Directory in business environments.

  • NSLOOKUP: To query a DNS server about the name or IP address of a device, you would use this command.