Troubleshooting Mobile Devices – CompTIA A+ 220-1101 – 5.5

We rely on our mobile devices for instant information. In this video, you’ll learn about troubleshooting poor battery life, broken screens, poor connectivity, and more.


Most of our mobile devices make use of batteries so we can continue to use these devices when we’re away from a power source. But unfortunately, the usefulness of that battery tends to degrade over time. Each time you recharge the battery, you’re losing a little more capacity in that battery each time. And after years of recharging, you’ll find that battery doesn’t seem to have the same capacity that it once did. In those cases, the best fix is to replace the battery in that device.

But there are things you can do to minimize this battery use even on systems that have a brand new battery. One of those is to be aware of the reception for your device. Whenever you go just outside the range of your provider’s network, your phone will lose the signal.

And your phone will constantly keep trying to reconnect to a signal that ultimately is not going to be there. Each time it does that, it’s using a little bit of the battery. And the longer you stay out of the range of that signal, the more of the battery you’re going to use.

If you know that you’re going to be outside the signal range for your provider, you may be able to save some of that battery by simply enabling airplane mode, even though you’re on the ground. This will disable the radios in your mobile device. It will stop constantly checking to see if there is a signal, and therefore save that much battery life just by turning on the airplane mode.

Airplane mode not only disables the cellular phone capability from your device, but very often will also disable 802.11 networking, Bluetooth, and GPS radios, as well. So by turning on one single switch on your mobile phone or your tablet, you’ll be able to save the battery that would normally be used by all of these different radios.

If you’re not sure exactly which applications may be using the most amount of your battery, you can check the built-in battery features on your mobile device. If you’re using iOS and iPadOS or Android, you’ll find all of those configuration options under Settings and Battery.

The battery that’s inside of your mobile phone or your tablet should look like the battery that’s here on the right. It’s relatively flat and can fit inside of those mobile devices. There may be times, though, where your battery will have a buildup of gas, and you’ll notice that the entire battery package will appear to be swollen.

This battery has been built by design to be able to capture and contain those gases if you happen to have a failing battery. You do not want to open or in any way puncture this particular package. Everything should be self-contained to avoid any type of fire risk.

You should, obviously, stop using this device and to replace this battery with a known good battery. This older and faulty battery should now be disposed of at your nearest hazardous waste facility. By containing all of these gases within the battery package itself, you’re avoiding any additional damage to this device.

Unfortunately, there may be times when the battery becomes so swollen that it does damage the device. In this case, you can see this phone has had the entire top of the phone come off because inside of it was a swollen battery. So although this battery may have damaged your device and, in some cases, require you to replace it, at least there were not any additional damage caused by a battery package that may have leaked or caught on fire.

The screens that are on our mobile devices are commonly made of glass. And because of that, there may be times when that glass happens to break. In those situations, you may need to replace the entire device or replace the screen itself. If your device is still functional, this would be a perfect time to perform a backup, especially since we don’t know what other damage may have occurred to this device.

Unfortunately, there’s no way to fix the glass that’s on the front. And very commonly, this glass is physically connected to the display that’s underneath. For that reason, we can’t just replace the glass. We have to replace the entire display to get this system back up and running.

If there’s any type of glass that is broken on the front of your device, be very careful about touching any part of it. That glass gets extremely sharp, and it’s very easy to cut yourself. You may want to take some clear tape and put over all parts of the glass that appear to be broken, that way you can at least use the device to some degree, especially if you’d like to perform a backup, without the fear of accidentally cutting yourself while you’re doing it.

There may be times when you connect a charger to your mobile phone, and it either doesn’t charge or charges very slowly. And in those cases, there are a number of troubleshooting tasks that can help you narrow down where the problem may be occurring. You can start with checking the interface itself, where you’re connecting your charging cable to the device. This can often collect dirt and lint and can prevent the charging process from working properly. You’ll certainly want to clean that out, but you want to be very careful not to disturb or damage any of the pins that are associated with that connector.

You’ll then want to check the cable that you’re using and make sure that it’s not damaged or has any fraying on it, and then make sure that the cable itself is one that you know to be operational. You may want to try it on another mobile device just to make sure that the cable that you’re bringing over is one that is a known good cable.

And if your device takes a long time to charge, it may not be getting enough voltage from the connector itself. You may want to pull out your multimeter and perform a few checks to see if you’re really getting the right voltage from your wall outlet and the right voltage from the connector that’s plugging into your mobile device.

There are a lot of variables that can affect the signal strength that we receive on a cellular network or a Wi-Fi network. Most of these variables revolve around where you happen to be at any particular moment. There may be a place inside of your building where you have fantastic reception. And then when you move to the other side of the building, you suddenly have no reception at all.

On a cellular connection, you’ll have a signal strength meter that can tell you just how much signal you happen to be receiving at your particular location. And that location matters quite a bit. If you’re inside of a building, it’s much more difficult for that signal to get to your device than if you happen to be outside.

Unlike cellular networks that have very large areas where you can receive a signal, Wi-Fi networks have a relatively limited range. And, of course, other devices that are either on that Wi-Fi network or use the same frequencies as that Wi-Fi network can also create interference that can affect your overall performance. If the interference you’re seeing is being created by other access points, you may want to change the channel or frequencies in use by your access point to see if you can have a cleaner signal, and therefore, better throughput to your access point.

One of the biggest enemies to our mobile phones and our tablets is liquid. And if you look at the warranty terms for your device, you’ll notice that water damage is not covered as part of your warranty. The phone manufacturers know this, and they have put inside of their devices liquid contact indicators, or LCIs. These are small sensors inside of your device that will turn a color if they happen to come in contact with any type of liquid. On phones and tablets, there will be multiple places inside of that device that contain one of these LCIs.

If you happen to get water on your device, you should power down that device immediately and do not plug it in or power it back on. You want to remove all of the different components that you can if this device has them, so remove the case, any cards, like a Sim card, get rid of a back of the device if you happen to have it. And if your device has a removable battery, make sure you remove that as well.

If you look online, it’s widely thought that you should be putting your phone into a bag of rice to be able to have it dry out. But in reality, rice does not do a very good job at removing large amounts of liquid in a small amount of time. You’d probably do much better to use a different type of desiccant, such as the silica gel packs, which are able to pull water much easily from the air.

Although putting your phone into a bag of rice doesn’t solve the water issue, it does solve the problem of you doing anything to this device while it has water inside of it. If there’s any chance of recovering this device after water damage, it’s to let the device completely dry out. This means you should not turn it on, you should not charge the phone, you should not connect it to any type of power source, press any keys that are on the device, do not heat the phone or the device, and do not move it around.

You should do nothing so that this device can properly dry itself out before ever providing any power source to the device. At a minimum, this should be a day where the device does nothing but sit in a very dry area and begin to dry itself out. If this device got very wet, then you may even want to wait just a little bit longer just to make sure that you have this device as dry as possible before attempting to power it on.

It could be that this device has already been damaged beyond repair. But this is your only opportunity to see if you could somehow get this device back up and running. So once you’re sure that it is completely dry, you can try powering it back on and see if the device happens to work.

Not only is water bad for our mobile devices, but heat is also bad for our mobile devices. Fortunately, there are sensors inside of our phones and our tablets that will keep track of how warm it is inside of those devices. And if it gets too warm, it will automatically turn itself off to prevent it from damaging the device further.

These devices create a lot of heat on their own. As you’re charging or discharging the battery, there is heat that’s created inside of these devices. As you’re using the CPU or using the display, there’s also heat that’s created on the inside of our phones and our tablets.

If you think there may be an app that’s causing a lot of heat inside of your device, there are app usage utilities on your phone and tablet that will tell you exactly how much CPU is being used by each individual app. You can then make the decision on whether you’d like to continue using that app or if you’d like to temporarily disable it.

In any of these cases, you should avoid putting your device in direct sunlight. This will heat up your phone or your tablet very quickly. And you’ll find that it will automatically shut down to prevent any damage.

There may be times when you’re trying to use your mobile phone and the screen is completely black. And you touch the phone, you press the buttons, and nothing seems to be responding to any type of input. In those cases, you may need to do a reset.

If this is an Apple device, you can hold down the Power button. You’ll get a message that says “Slide to power off.” And then once it’s powered down, you can press the Power button to power it back on.

But, of course, if this screen is black and there’s nothing to see on the screen, you may not be able to do a soft reset. Instead, you need to perform a hard reset. On many Apple devices, you would hold down the Power button and hold at the same time the Home or the Volume button for 10 seconds. It will then automatically reset itself. And you should see the Apple logo as it’s booting back up.

The process on an Android device is very similar. If it has a removable battery, you can simply pop out the battery, which certainly performs a hard reset, and then put the battery back in and restart the phone. There are also other reset options, depending on the manufacturer of the Android device. But one very common reset is to hold down the Power and Volume buttons until the system restarts. There may be different combinations, depending on your phone, so check the documentation for your device.

Our phones and our tablets are designed to be mobile devices so they can deal with a good bit of wear and tear. But there may be times when the interfaces on these devices may become damaged. You may notice that when you’re trying to charge the device, that it only charges if the cable is put in in a certain way, or maybe the data transfer function is no longer working from that device.

This may have been caused by someone tripping over a charging cord or someone who accidentally dropped the device on the floor. You may be able to look very closely at the inside of the interface to see if there’s any bent pins or any damage to the interface inside.

But one of the problems with these types of interfaces is that they’re built into the system board of the device itself. So to replace that single interface, you would very commonly have to replace the entire system board. It’s very unusual to find someone who may have the tools and the expertise to be able to replace just that interface on the system board. So very often, it requires an entire replacement of the system board just to replace that individual interface.

One challenge we have with all of our devices, mobile or otherwise, is the threat of malware and other malicious applications. There are a number of symptoms we can look for to see if this device may have been infected by malware. We can see if there’s any unusual applications that we didn’t install.

If we look at reports of data transfer, we may notice that certain applications may be transferring more than usual, or the overall data transfer rate is much more than we might expect. You should also check to see if there’s unusual pop-up messages appearing on your screen, or if your device has very high CPU usage, or tends to be overheating more than usual.

And, of course, if your battery continues to be depleted, that may indicate that some other process is running constantly on your mobile device. If there’s no obvious malware symptom, then you may want to run a third-party application or virus scanner to see if it can identify anything unusual that may be loaded on your device.

One annoying problem that can cause your device to do things you weren’t expecting is the problem of cursor drift. This is when your device is still, there’s nobody touching the device, but you notice that the cursor is moving around the screen. This was very common on older technologies that needed constant calibration to be able to prevent this type of drifting.

There’s usually a calibration app built into the device that asks you to touch different places on the screen to recalibrate what it expects when people are providing any input. And this will usually stop any type of random input or cursor drift, and your device will go back to normal operation.