Troubleshooting Common Mobile Device Issues | CompTIA A+ 220-1001 | 5.5

In this video you will learn about common mobile device issues.

Common Symptoms

No Display

No display on a laptop can be caused by a variety of issues such as:

  • Failure of LCD inverter or backlight
  • Damaged cables connecting to LCD inverter
  • Failure of LED control board
  • Display panel failure
  • Onboard display circuit failure
  • Laptop being toggled to use an external display with a Function key

To fix these issues:

  • Try toggling the laptop to use internal display
  • Try connecting it to a monitor or projector
  • If external display works
    • Issue may be with LCD-CCFL backlight on LED control board or LED backlight
    • If external display doesn’t work
      • Motherboard needs to be repaired or replaced

If a tablet or smartphone has a no display issue, it is usually due to the unit being out of power.  To fix:

  • Connect to a charger
  • Wait about 10 minutes & power it on
  • If there’s still no display, the device needs to be serviced or replaced

Dim Display

To fix dim display issues:

  • Check the brightness settings of the device
  • Check the Auto power management settings of the device
  • Make sure the ambient light sensor is working & is not being blocked
  • Check the battery level to see if the mobile device is about to run out of power
    • Most devices dim the screen in order to preserve the last bit of battery left on the device before it shuts down
    • After recharging the device, if the device doesn’t return to normal brightness, service the device or replace it

Dim displays not caused by user settings is usually attributed to the backlight inverter failing on the device. If this is the case, you will have to service or replace the device.

Flickering Display

Flickering displays on laptops with LCD-CCFL backlights is primarily due to a dying backlight. Damaged LCD ribbon cables connected to the motherboard could also be a reason for flickering display issues. The solution to fixing it is to simply replace the entire screen assembly for a new one.

Sticking Keys

Fixing sticking keys, you can find online vendors who offer individual key replacements for laptops. If your keyboard has multiple sticking keys, it is often times cheaper to simply replace the entire keyboard.

Intermittent Wireless

If the mobile device is experiencing intermittent WiFi due to weak WiFi signals, if the device has a cellular data connection, switch to the cellular data until a stronger WiFi signal becomes available. Also you can use wireless signal strength indicators to find strong WiFi signals.

Battery Not Charging

To fix a battery that is not charging on a mobile device:

  • Make sure the charger is the proper charger for the tablet or smartphone.
  • Make sure the charging port on the device is clean and doesn’t have dirt, dust, or debris in it.
  • If the charger has a toggle for iOS and non-iOS devices, choose the correct setting for your device.
  • Make sure that the USB port on the laptop or desktop computer is enabled for USB fast charging if that option is available, and use that port for charging your device.
  • Check to make sure your charging cables are not damaged & actually work. If they don’t work, replace the cable.
  • Replace the battery or have the device serviced if a working cable doesn’t solve the issue.
  • Make sure battery is properly installed.
  • Clean dirt & corrosion on battery & laptop battery contacts.
  • If the battery is hot after being charged or has a warped exterior, replace it.

Ghost Cursor/Pointer Drift

Moving the mouse too fast on the screen can cause a ghost cursor. To fix this issue:

  • Adjust the mouse properties to slow down the acceleration of the mouse
  • Use a larger mouse pointer
  • Enable visibility options (pointer trails)
  • Press the Ctrl key to display the mouse location

Accidentally swiping, pressing on a device’s touchpad, or issues with a device’s integrated pointing stick can cause pointer drift problems. To fix this issue, disable the touchpad or change its sensitivity settings to ignore accidental touches.

No Power

If a laptop has no power:

  • Verify that the battery is not the issue
  • Make sure laptop is plugged into a working AC outlet
  • Make sure AC power cord running from AC outlet to the external AC adapter “power brick” is plugged in completely to the outlet & adapter.
  • If power cord is damaged, replace it.

Num Lock Indicator Lights

Num lock indicator lights not turning on could signal that there may be a problem with the keyboard. If so, simply swap out the keyboard

No Wireless Connectivity

To fix:

  • Check laptop for push button, pressure-sensitive touch button, or Function key to enable/disable WiFi
  • Check to make sure Airplane mode is turned off
  • Check to make sure WiFi & cellular radios are turned on
  • Check WiFi connection/signal in your area
  • If having WiFi issues on laptop
    • Open access panels to check to make sure WiFi antennas are properly connected to WiFi card

No Bluetooth Connectivity

To fix Bluetooth connectivity issues on laptops:

  • Press the Bluetooth button or Fn key combo to enable the connection.
  • Verify that Bluetooth adapter is installed & enabled.
  • If the Bluetooth adapter is installed, use the Bluetooth configuration utility provided by the computer vendor to set up the adapter to connect to other devices.
  • If the adapter is already set up to connect to other devices, check the Bluetooth settings on those devices.
  • Check to see if Airplane mode is on, if so, turn it off.

Cannot Display to External Monitor

To fix issues with displaying to an external monitor:

  • Use the appropriate keyboard Fn key combination after connecting the display or projector.
  • Check the cabling between the computer and the external display.
  • Make sure the display is set to the correct input.
  • Try a different display to determine if the problem is the mobile device or the external monitor.

Touchscreen Non-Responsive

Dust, dirt, & grease on the surface of a touchscreen is the most common reason for a touchscreen to be non-responsive. To fix:

  • Use antistatic wipes or spray designed for touchscreens to clean it.
  • Use a stylus made for the touchscreen. If the stylus doesn’t work:
    • Power off & power back on device.
    • If stylus still doesn’t work, service the device or replace it.

Apps Not Loading

To solve problems with apps not loading:

  • Check available storage space.  Uninstall apps you never use.
  • Close apps that you are not actively using to free up RAM.
  • For web-enabled apps, be sure to have a good internet connection.

Slow Performance

To fix slow performance:

  • Remove the case and close apps to help cool the device.
  • Check the power management settings.
  • Close apps that are running but not in use.
  • Close apps before charging the phone.

Unable to Decrypt Email

Missing or out-of-date security certificates on devices can cause issues with decrypting email.  Update security certificates to solve this problem.

Extremely Short Battery Life

Issues with extremely short batter life:

  • Don’t overcharge a device’s battery.
  • Don’t wait until a device is almost out of power to charge it.
  • Adjust screen brightness to the lowest comfortable level.
  • On iOS devices, turn off background app refresh.
  • Upgrade to the latest OS or OS updates available for your device.
  • Use a phone battery helper app to manage charging.
  • Close apps from the iOS App Switcher.
  • Shut down an iOS device weekly with the slider switch.
  • Extreme cold can drain a battery. Be sure to take weather conditions into consideration.


Mobile device overheating can cause several issues:

  • Make sure the intake and exhaust fan ports on laptops aren’t being blocked during use.
  • When running off of battery power, adjust power settings.
  • Make sure CPU power management drivers are installed.
  • On a tablet or smartphone, shut down unnecessary apps. 
  • Some protective cases can cause smartphones to overheat.

Frozen System

Malfunctioning apps typically are responsible for frozen systems. To fix:

  • Go to the lock screen for a few seconds to help the mobile app start responding.
  • If that doesn’t work
    • Shut down the system, then restart.
    • Check for updates for the app & device.

No Sound from Speakers

No sound from speakers can have several causes:

  • Check the volume or mute controls on laptop or other mobile devices.
  • If using Bluetooth speakers, make sure Bluetooth is turned on & then check the device pairing.
  • With wired speakers, the case might prevent 3.5mm mini-jack connector from making a good connection.  It may be necessary to remove the case to make a good connection.

GPS Not Functioning

If the GPS is not working:

  • Check to make sure Airplane mode is turned off.
    • Airplane mode will disable GPS.
    • Turn on GPS in Settings > Location menu.

Swollen Battery

Overcharging is typically responsible for a battery being swollen. In addition to replacing the battery, check the AC adapter to make sure it is putting out the correct voltage.

Disassembling Processes for Proper Reassembly

Document & Label Cable and Screw Locations

Laptops and smartphones typically have a lot of screws of varying sizes. Make sure to properly document & label the cable, annotate its size & screw locations. You can use a digital camera or smartphone as a tool to help document the process.

Organize Parts

Ways to organize parts:

  • Use a plastic divided-compartment tray from a hardware store to keep screws and bolts organized.
  • Place static-sensitive materials (CPU, RAM, etc) in antistatic bags.
  • Use antistatic bubble wrap for larger components, such as motherboards.
  • Use boxes to protect case and trim components.

Refer to Manufacturer Resources

Refer to the manufacturer resources before disassembling a device:

  • Get the manufacturer’s service manual, if it is available.
  • Check the underside of a laptop or tablet to find the service or catalog number (not the marketing model number).

Use Appropriate Hand Tools

Always use appropriate hand tools for disassembling mobile devices. They are smaller and differ in other ways from those needed for a desktop computer.

Mobile Phone Tool Kit