220-1101 Mobile Devices Practice Test 11 — 15 Questions

Question 1

A user's smartphone will not charge when plugged into a cable. The technician inspects the charging port and finds it is clean and the cable appears undamaged. The phone was working normally earlier and was not dropped. The technician tests the cable with another device and it charges normally. Which of the following should the technician do NEXT to diagnose the issue?

Accepted Answer

Test the phone with a different, known-good charger and cable. Since the cable works with another device and the charging port is clean, the issue is isolated to the phone's charging circuit or battery management system. Testing with a known-good charger and cable eliminates variables and confirms whether the phone itself is rejecting power, which is the standard next step in CompTIA A+ troubleshooting methodology.

Answer

Replace the battery with a new one

Answer

Perform a factory reset of the smartphone

Answer

Replace the charging port assembly

Question 2

A technician sets up a smartphone for a user who wants to connect a Bluetooth keyboard and mouse. After pairing both devices, the user reports that typing on the keyboard produces random characters or repeated letters. The technician verifies that both devices are paired and show good battery levels. Which of the following is the MOST likely cause of this issue?

Accepted Answer

The phone does not properly support both a Bluetooth keyboard and mouse simultaneously. The most likely cause is that the smartphone does not properly support simultaneous Bluetooth keyboard and mouse connections. Many mobile operating systems or Bluetooth stacks have limitations on the number or type of HID (Human Interface Device) profiles they can handle concurrently, especially when both are input devices. This can lead to input conflicts, such as repeated or random characters, even when both devices are paired and have sufficient battery.

Answer

Bluetooth interference from other wireless devices in the area

Answer

The keyboard has a low battery

Answer

The phone's screen is dirty

Question 3

A technician replaced the screen assembly on a smartphone. After reassembly, the phone powers on and displays correctly, but the touch screen is unresponsive. Which of the following should the technician check FIRST?

Accepted Answer

Ensure the digitizer ribbon cable is properly seated. The digitizer ribbon cable connects the touch-sensitive layer of the screen to the motherboard. If it is loose or improperly seated after reassembly, the touch input cannot be registered even though the display (LCD/OLED) works fine. This is the most likely cause given the recent disassembly and should be checked first before any software or replacement steps.

Answer

Reboot the phone into safe mode

Answer

Update the touch screen drivers

Answer

Replace the screen assembly again

Question 4

A user's smartphone screen is cracked and the touch is unresponsive in the cracked area. The technician replaces the screen assembly. After reassembly, the phone powers on, displays correctly, but the touch still does not work in the same area. What should the technician check first?

Accepted Answer

Digitizer cable connection. The correct answer is A because the digitizer is the component responsible for touch input, and it connects to the mainboard via a separate cable from the LCD. If the touch remains unresponsive in the same area after replacing the screen assembly, the most likely cause is a loose, damaged, or improperly seated digitizer cable connection. The display works correctly, which confirms the LCD cable is fine, isolating the issue to the digitizer.

Answer

LCD cable connection

Answer

Battery connection

Answer

Proximity sensor

Question 5

A user reports that their smartphone's Bluetooth will not enable. When the user taps the Bluetooth toggle in the Quick Settings panel, it briefly turns blue and then immediately turns gray. The phone did not get wet and was not dropped recently. Which of the following should the technician check FIRST?

Accepted Answer

Restart the smartphone. When Bluetooth fails to enable and the toggle immediately reverts, it often indicates a driver or firmware issue. The first step in troubleshooting should be to restart the device, as this clears temporary software glitches. If that does not work, checking for OS updates is the next step, as updates often include driver fixes. Replacing the battery is unlikely to help unless the battery is swollen (which would usually cause other symptoms). Resetting network settings is a more invasive step that should be done after trying a simple restart and updates.

Answer

Replace the battery

Answer

Check for operating system updates

Answer

Reset network settings

Question 6

A technician replaces the digitizer on a smartphone that had a cracked screen and an unresponsive touch area. After reassembly, the touch screen still does not respond in the area where the crack was. The technician has already verified that all flex cable connections to the digitizer are secure. Which of the following should the technician do NEXT?

Accepted Answer

Test the phone with a known-good digitizer. Option C is correct because the technician has already verified that all flex cable connections to the digitizer are secure, yet the touch screen remains unresponsive in the same area. This indicates the replacement digitizer itself may be defective. Testing with a known-good digitizer isolates the issue to the digitizer component versus the phone's main board or software, following a logical hardware troubleshooting process.

Answer

Replace the LCD assembly

Answer

Calibrate the touch screen in the operating system

Answer

Update the phone's firmware

Question 7

A user reports that their smartphone’s battery drains very quickly, even when not actively in use. The technician notes that the device feels warm to the touch, the screen brightness is set to maximum, and several apps are running in the background. The device is running the latest OS version. Which of the following should the technician recommend as the FIRST step to address the battery drain?

Accepted Answer

Reduce the screen brightness and close unused background apps. The most immediate and effective first step is to reduce screen brightness and close unused background apps because the display is the largest power consumer in a smartphone, and background apps can keep the CPU active, generating heat and draining the battery. Since the device is already on the latest OS version and the symptoms point to user-configurable settings rather than hardware failure, this non-invasive step directly addresses the two most likely causes of rapid drain.

Answer

Replace the battery with a new OEM battery

Answer

Perform a factory reset and restore from a recent backup

Answer

Update the device’s operating system

Question 8

A user reports that their smartphone battery percentage jumps erratically—for example, showing 50% then suddenly dropping to 10% and shutting down. The technician verifies the battery is not swollen, the charging port is clean, and the device charges normally. Which of the following should the technician try NEXT?

Accepted Answer

Calibrate the battery. The erratic battery percentage drop without physical swelling or charging issues indicates a software calibration problem, not a hardware failure. Calibrating the battery resets the fuel gauge chip's learned capacity values, allowing the operating system to accurately report charge levels. This is the correct next step before replacing the battery.

Answer

Replace the battery

Answer

Update firmware

Answer

Replace the charging port

Question 9

A user wants to synchronize their smartphone's contacts and calendar with their company's Microsoft Exchange server. Which protocol is specifically designed to provide this synchronization?

Accepted Answer

Exchange ActiveSync. Exchange ActiveSync (EAS) is a Microsoft protocol specifically designed to synchronize email, contacts, calendar, tasks, and notes between mobile devices and an Exchange server. It uses HTTP(S) and supports push synchronization, remote wipe, and policy enforcement, making it the correct choice for syncing contacts and calendar with a company's Exchange environment.

Answer

IMAP

Answer

POP3

Answer

SMTP

Question 10

A user reports that their smartphone's touch screen stopped working after the phone was briefly submerged in water. The technician dried the device thoroughly, then replaced the screen assembly (including the digitizer) with a known-good part. After reassembly, the touch screen is still completely unresponsive. The display works correctly, and the phone powers on and charges normally. Which of the following components should the technician check next?

Accepted Answer

The motherboard's touch screen controller IC. The correct answer is C because water damage can short or corrode the touch screen controller IC on the motherboard, which processes signals from the digitizer. Since the display and other functions work, the issue is isolated to the touch input path, and replacing the screen assembly (including the digitizer) did not resolve it, pointing to a damaged controller IC rather than the peripheral components.

Answer

The battery

Answer

The charging port

Answer

The SIM card slot

Question 11

A user reports that their smartphone's battery life has significantly decreased after a recent OS update. The technician observes that location services and background app refresh are enabled. Which of the following should the technician do FIRST to address the issue?

Accepted Answer

Check the battery health status in the device settings. Before taking more invasive steps such as disabling all background processes or performing a factory reset, the technician should first check the battery health status in the device settings. Modern smartphones include a battery health feature that indicates the maximum capacity and whether the battery needs to be replaced. This helps determine if the battery is physically degraded, which could be the root cause of poor battery life, especially after an OS update that may have changed power management. If the battery health is good, then software settings like location services or background app refresh can be adjusted.

Answer

Calibrate the battery by fully draining it and then charging it to 100%

Answer

Disable all background app refresh settings

Answer

Perform a factory reset of the smartphone

Question 12

A user's smartphone is unable to make or receive calls. The device shows full signal bars but when attempting to place a call, it immediately ends. The technician checks airplane mode and it is off. Which of the following should the technician check FIRST?

Accepted Answer

Check the SIM card.. Full signal bars indicate the device is connected to the cellular network at the RF level, but an immediate call failure suggests the device cannot register with the network for voice services. The SIM card contains the IMSI and authentication keys (Ki) required for network registration; if it is loose, damaged, or not properly seated, the phone will show signal bars from the base station but fail to complete call setup because the network rejects the unauthenticated device.

Answer

Reboot the phone.

Answer

Check the Bluetooth settings.

Answer

Check the Wi-Fi calling settings.

Question 13

A technician is repairing a smartphone with a cracked screen. After replacing the screen assembly, the touch screen is completely unresponsive, although the display shows properly. The technician has verified that the digitizer flex cable is firmly seated in the connector on the motherboard. Which of the following should the technician check NEXT?

Accepted Answer

Check that the grounding screw for the digitizer is installed and tight. Option C is correct because many smartphone digitizer assemblies require a dedicated grounding screw to complete the circuit for capacitive touch sensing. Without this ground, the digitizer may receive power and data via the flex cable but cannot establish a stable reference voltage, causing the touch screen to be completely unresponsive even though the display works. The technician has already verified the flex cable connection, so checking the grounding screw is the logical next step.

Answer

Check that the LCD cable is properly connected

Answer

Check the digitizer cable for damage or improper orientation

Answer

Replace the battery

Question 14

A user reports that their smartphone's Bluetooth will not pair with their car's hands-free system after a recent OS update. The car's system has been successfully paired with other phones. The technician has reset the phone's network settings and forgotten the car from the Bluetooth list, but the pairing still fails. Which of the following should the technician try NEXT?

Accepted Answer

Check for a firmware update for the car's infotainment system. The car's system works with other phones, so the issue is likely an incompatibility introduced by the smartphone's OS update. Checking for a firmware update for the car's infotainment system is the next logical step because the car's Bluetooth stack may need an update to maintain compatibility with the new OS version's Bluetooth profiles or security requirements (e.g., LE Secure Connections).

Answer

Perform a factory reset of the smartphone

Answer

Replace the Bluetooth antenna in the smartphone

Answer

Disable Wi-Fi on the smartphone before pairing

Question 15

A technician replaced the cracked display on a smartphone. After reassembly, the touchscreen works perfectly, but the physical home button (which also houses the fingerprint sensor) does not respond to presses. The display and touch functionality are normal. Which of the following components is MOST likely the cause of this issue?

Accepted Answer

The home button flex cable. The home button flex cable is the dedicated connection for both the physical button's tactile input and the fingerprint sensor. Since the display and touchscreen work fine, the digitizer and LCD cables are intact, and the battery connector is not related to button functionality. A damaged or improperly seated home button flex cable would prevent the button from registering presses while leaving other functions unaffected.

Answer

The digitizer flex cable

Answer

The battery connector

Answer

The LCD cable