CompTIA A+ Exam 220-902 sub-objective 4.3 – Given a scenario, troubleshoot mobile OS and application issues with appropriate tools

Back to the main 902 ExamNotes page

Detailed (and official) description of CompTIA A+ sub-objective 4.3

4.3 Given a scenario, troubleshoot common mobile OS and application issues with appropriate tools.

Common symptoms
Dim display
Intermittent wireless
No wireless connectivity
No Bluetooth connectivity
Cannot broadcast 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
Inaccurate touch screen response
System lockout

Tools
Hard reset
Soft reset
Close running applications
Reset to factory default
Adjust configurations/settings
Uninstall/reinstall apps
Force stop

Welcome to ExamNotes by CertBlaster! This section will treat the 220-902 Objective “4.3 Given a scenario, troubleshoot common mobile OS and application issues with appropriate tools.”We will examine the symptoms of mobile device problems and the tools that can be used to mitigate them. We cover the systems to be addressed based on their representation in the objectives. Here is how that breaks down. The lion’s share of the mobile market belongs to the Linux-based Android OS followed by Apple’s iOS with the Windows platform coming in as the third.  There are of course other OSs that are proprietary to a manufacturer.

Common symptoms

The goal here is to alleviate issues experienced on mobile devices, like Smartphones and tablets that run mobile operating systems (OS). These operating systems are optimized for mobile device architecture and features including interoperability with other devices. When we address a condition or tool it will generally be applicable to all of the covered platforms. If a particular item is brand or OS specific we will point that out. Let’s look at the symptoms.

Dim display

When you find the screen difficult to read properly in a dark room there could be several causes. The screen brightness could be set too low. Always check this first. The adaptive or automatic brightness control could be malfunctioning or set too aggressively. The battery saver will also change the brightness. Turn these features off to see if the condition improves. If it does, change the settings to something easier to read.

Intermittent wireless

When you have an unreliable wireless connection first confirm that the desired network is working and visible. Then it is always best to use the system tools to diagnose the desired connection’s signal strength. For Android this can be found in Settings> About phone> then check the Status of the phone or SIM. The wireless signal strength, measured in decibels (dB). A lower dB reading of -30 will be better than a high reading of -70. The connection strength can be compared to other available networks by checking the available list. The networks displayed show wireless signal strength indicators as bars, more bars equals a better signal. Assuming your signal strength is sufficient you should check the network settings. For the connected device, you will be able to view and reset the IP address. If that fails, use the Forget option will clear all related settings for the network and then you can reestablish them. If the network is saved the connection will be automatic. To connect to a Wi-Fi network from the available list the SSID will be displayed. For hidden networks, you will need to manually enter the SSID and Passphrase. Make sure you are not dropping your wireless connection when the device sleeps. Set the Keep Wi-Fi on when device sleeps to On. When all else fails, use the soft reset method, evaluate then as a last resort follow-up with the hard reset.

No wireless connectivity

The “No wireless connectivity” condition differs from “Intermittent wireless” in that we cannot assume that both devices are on and transmitting. That needs to be established first. Your WAP should be seen by your mobile device. If not validate the router operation with a second device. Make sure you have the right SSID and passkey/password. When you cannot establish a wireless connection at all the number one answer is Airplane Mode.  It is surprisingly easy to turn this mode on. It will appear as an Airplane icon in your notification bar when active. When it is on Airplane Mode disables all wireless communication to the device. This includes Wi-Fi, Cellular, Bluetooth, NFC, and GPS. After that, the same methods that apply to an intermittent connection are valid here.

No bluetooth connectivity

With Bluetooth, the devices connect by pairing with each other while they are in Discovery mode. We’ll go over that term shortly. When devices are not paired it is possible that they can’t see each other. For security and power management Bluetooth devices only remain visible to unpaired devices for roughly two minutes after startup, this is called Discovery mode or pairing mode, and after that time the device will only be seen by paired devices. The visibility time can be set to provide more time if needed. It’s easy to initiate the pairing process for a headset by cycling the power off and on or pressing a designated button or button combination. However, on a smartphone or tablet, you should activate Discovery mode in the Bluetooth >Settings of the device for it to remain visible to all devices and scan for connections for the allotted time, this will usually be two minutes but can be adjusted if you need more time. Both devices need to be in Discovery mode at the same time. At the first pairing Bluetooth creates a very small network of between two and eight devices known as a Personal Area Network (PAN), also called a piconet. The paired devices will remember each other and pair automatically. Retry pairing when paired devices do not automatically connect. If this fails you may have to “Forget” the existing pairing and start fresh.

Cannot broadcast to external monitor

The capability to broadcast your smartphone’s screen wirelessly to a monitor or smart TV can be accomplished either using a hardware adapter on the Monitor and/or software app installed on the phone. Wi-Fi Direct and Wireless Display (WiDi) technology have made this capability almost routine. Hardware device based methods like Chromecast, Miracast or Apple’s Airplay use a dongle attached to the display to mirror or stream the content. Other newer devices have the capability built in. There is a difference in the technologies. Miracast technology displays your mobile device screen to the HDTV or monitor. In this case, the device has to remain awake or active. When your mobile screen goes blank the display does also. Chromecast uses your mobile device to identify the desired content. Once it finds the content Chromecast streams it to the TV and your phone is no longer necessary. This represents significant mobile battery savings.

Problems you could encounter come from third-party VPN software. Some cloud-based services install a VPN during setup. VPN programs regard WiFi Direct (used by Miracast) a threat and disable them. The first troubleshooting step is to make sure both devices are supported by the respective manufacturers. Then check for VPN services running on the mobile device and stop them. If you are still unsuccessful you may have to uninstall the VPN package.

Touchscreen non-responsive

A non-responsive touch screen can have a variety of causes, to get back in First if you have a screen protector, remove it. If you are wearing gloves or your hands are wet resolve that first. Then clean the screen and your hands thoroughly.  Evaluate operation.  If unresolved turn the device off. Don’t reinstall the screen protector until it can be ruled out as a problem, Restart the device and recalibrate the screen if necessary.

Apps not loading

If you have a condition where apps will not load or load slowly, the first thing to check is the amount of available storage on the device. Cached app files can get large and should be cleared periodically. Resources are finite and unused apps should be uninstalled to free up storage space.

App loading animation
App loading

Slow performance

Over time your mobile device may feel like it is slowing down. This condition can most often be resolved by restarting the device. This is because an app disappears from view when a new app is launched and does not close. The old app remains running in the background and is consuming resources. If restarting is not an option use the action bar to view your running apps. Between restarts, you will open quite a few apps. Manufacturers recommend restarting the device regularly to minimize this condition.

Unable to decrypt email

Since email encryption depends on Public and Private Keys. These would be the first areas to check when there is a failure in the decryption process. In this case, the private key stored on your device does not use your previously distributed public key. In most cases, the simplest solution would be to generate new public/private keys and distribute the public key to those individuals you communicate with using encryption.

Extremely short battery life

In cases where you feel your battery life between charges has decreased, the first consideration is what kind of load the battery is supporting. Apps and services use battery services. Stop all apps running in the background and disable unused Bluetooth and Wi-Fi connections. The wireless and Bluetooth transmissions consume a lot of battery resources. Follow the steps above and reevaluate the condition. Also consider here the age of the battery. Old batteries do not hold a charge as long as new ones.

Icon for Battery running low
Battery running low

Overheating

Overheating can result from running too many background apps running, having you display on for extended periods or when charging. Having your screen active for too long will cause the device to heat up. Close all unneeded apps running in the background, turn the display off, let device cool and evaluate. A device that gets hot when charging should be disconnected immediately. Very importantly examine the battery carefully for signs of swelling, which is a dangerous condition. Remove the battery and allow it to cool to room temperature. If the battery is swollen replace it immediately. Do not take chances with a swollen battery. If it is not swollen reinstall the battery and re-evaluate the condition. Try using a different charger and cable, as one of those may be defective. If the problem persists have the device serviced or the battery replaced.

Frozen system

When your system freezes once simply restart and see if the device behaves. If it doesn’t try checking that you have sufficient free storage and perform a manual OS update check. Install any available updates and evaluate. Determine if the problem is with the system or the installed apps. Follow the device manufacturer’s instructions for starting the device in safe mode. Safe mode starts the device using only the installed operating system at the manufacturer’s defaults. If the problem disappears. You know the problem is with the installed third party apps. Restart and begin to remove the installed apps. Begin with anything installed around the time the problem presented.

No sound from speakers

When you have no sound on your device the first thing to check is the volume setting. Be sure the speakers are not muted. Check the physical control then check your sound settings. Audio problems of this nature can also result from the audio output being redirected to Bluetooth.

No audio icon
No audio

Inaccurate touch screen response

Your touch screen responsiveness and accuracy depend on whether it uses capacitive or resistive technology. The majority of devices use capacitive touch screens. These screens determine your taps based on the electrical charge of your skin and are quite accurate. Seldom requiring alignment in normal conditions. Capacitive touch-screen response can be influenced by things like screen protectors, rubber gloves, and wet hands. Make sure your screen is clean and your hands are dry and not gloved. Resistive touch screens use two clear conductive sheets to determine your contact by using the points that the two screens touch based on the pressure of your finger or stylus. Resistive screens need to be calibrated using system tools. Resistive screens are preferred in environments where the user’s hands are damp or gloved.

System lockout

Repeated bad unlock attempt will cause protected devices to lock either for a predetermined length of time or permanently depending on how your configuration is set. For Android devices, access can be restored by using your Google account or getting an app from the play store. Apple iOS devices, on the other hand, require the device to be reset to factory defaults.

Tools

Soft reset

Always the first choice for resets a soft reset can resolve many system issues including phone problems email problems and sound for starters. It can also recover your system from a locked app situation or repair network connections. Performing a soft reset is simply a matter of power cycling to restart the system. Your data and programs will remain intact and your system should behave normally.

Hard reset

A hard reset also referred to as a factory reset for Android, and It will hibernate then restart in iOS. For Android, it is the most invasive of the commonly used resets. A hard reset will be your last hope of using a corrupted or malfunctioning device at the expense of losing your data. Back it up if you can. It works by completely wiping the device of all user data and settings.  Using this method you restore the system to it’s out of the box factory configuration with all of your apps, data, and settings gone. The hard reset in Android devices is irreversible. With this in mind always keep your content synced with the cloud storage provider of choice, Dropbox, iCloud or Google Drive. Once it’s gone, it’s gone.

Close running applications

In a troubleshooting situation, it’s a good policy close any app running on your device and consuming resources. The resources used by several running apps may be sufficient to prevent another app from loading or running properly. All mobile devices provide the user the ability to either close all running apps or stop them selectively. Closing all running apps is the best way to prevent software conflicts while testing. The apps needed can be launched individually to try and reproduce an issue.

Reset to factory default

This topic is covered above under the “Hard reset” section.

Adjust configurations/settings

All mobile devices provide access to system configuration and settings. E.g. For a dim display check the automatic brightness control in Settings. For wireless signals -30 dB is better than -70 dB, so choose the lowest dB value signal you can get. Geolocation settings can be changed. Practically all system operations have some level of user control. Always change settings one at a time to enable you to review the results of new or changed settings.

Uninstall/reinstall apps

When you have an app that you consider to be a problem it is good to uninstall it and reinstall it using iTunes App Store or the Google Play Store for Android. This process ensures a clean download and fresh installation.

Force stop

It’s always good to keep the running apps to the minimum possible number. Multiple apps running reduces performance as noted earlier. Follow the device/OS instructions for this process and be vigilant about how many apps are running.

Back to the main 902 ExamNotes page

Leave a Reply

Your email address will not be published. Required fields are marked *

On Facebook

Share This
Real Time Web Analytics