Page 3 901 Hardware and Network Troubleshooting Study Guide for the CompTIA® A+ exam

Mobile Device Issues

For this section, you should be able to troubleshoot common issues with mobile devices in any given scenario. You should also be aware of the proper procedures to use.

Common Symptoms

You should be able to diagnose these common symptoms associated with mobile devices.

  • no display
  • display
  • flickering display
  • sticking keys
  • intermittent wireless
  • battery not charging
  • ghost cursor/pointer drift
  • no power
  • num lock indicator lights
  • no wireless connectivity
  • no Bluetooth connectivity
  • cannot display to external monitor
  • touchscreen non-responsive
  • apps not loading
  • slow performance
  • unable to decrypt email
  • extremely short battery life
  • overheating
  • frozen system
  • no sound from speakers
  • GPS not functioning
  • swollen battery


For this section, you should be aware of proper disassembly procedures that will enable appropriate reassembly after repair.

  • document and label cable and screw locations: It is important to document what you are doing as you are taking apart a mobile device. You should include locations of all parts, and label any pieces that you remove. These tiny parts are typically very easy to remove, but get complex and confusing when it comes to reassembling everything. You could even take pictures, if it will help you remember exactly where a part goes.

  • organize parts: Many professionals make use of organization bins to sort and store all of the various parts when disassembling a mobile device. This is another way to help keep you organized, and help you remember the location of each part.

  • refer to manufacturer resources: If you have trouble knowing exactly what to take apart, or you would just like some extra information, always feel free to consult the manufacturer’s documentation. This can be paper documentation or gleaned online from their website.

  • use appropriate hand tools: Mobile devices often have their own specialized set of tools with which to work. This tools are especially important, as they are made specifically for the mobile equipment. Standard tools may not work or they may damage the delicate mobile parts.

Printer Issues

For this section, you must be able to troubleshoot and diagnose problems with printers in any given scenario. There is a variety of printer types and functions and their repair is type-specific.

Common Symptoms

For this type of question, you should be comfortable identifying common symptoms associated with printer issues. Here are some issues you may see.

  • streaks
  • faded prints
  • ghost images
  • toner not fused to the paper
  • creased paper
  • paper not feeding
  • paper jam
  • no connectivity
  • garbled characters on paper
  • vertical lines on page
  • backed up print queue
  • low memory errors
  • access denied
  • printer won’t print
  • color prints in wrong print color
  • unable to install printer
  • error codes
  • printing blank pages
  • no image on printer display


You should be very familiar with the common tools used to work with printers, as they will aid you in resolving issues.

  • maintenance kit: This is a common kit used for performing maintenance on laser printers. It typically includes several replacement parts, such as new feed rollers, toner and fuser units.

  • toner vacuum: A specialized vacuum can be used for removing toner dust from inside your printer. It includes a special filter and is anti-static, so that it won’t damage any components in the printer.

  • compressed air: This provides a high-pressure force of air to clean out components of your printer, and other computer hardware. It is usually made of fluorocarbon gas that is typically compressed inside an aluminum bottle. When used on printers, it is best to do this outside in an open area, so that toner particles or paper dust won’t make a mess inside the office.

  • printer spooler: This service in the operating system manages the printing in the background. It can be stopped or restarted, if you are having trouble sending print jobs to the printer.