220-1101 Mobile Devices Practice Question
A technician needs to replace a cracked LCD screen on an Android smartphone. After disassembling the phone and disconnecting the old screen, which of the following should the technician do FIRST before installing the new screen?
⚠ Common exam trap
Test-takers frequently think testing the screen immediately (Option A) is the logical next step to confirm functionality, but CompTIA emphasizes safety and proper procedure by requiring battery disconnection first to prevent damage from residual power.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Remove or disconnect the battery
The correct first step before installing a new screen is to remove or disconnect the battery. This ensures the device is completely powered off and eliminates the risk of short circuits or electrostatic discharge (ESD) that could damage the new LCD or other sensitive components during installation. Even if the phone appears off, residual charge in capacitors can cause damage if the battery remains connected.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Connect the new screen and test the display immediately
Why it's wrong here
Connecting the new screen and testing the display immediately is only wrong because the battery is still attached—the test itself is necessary and correct, but the timing is the hazard. When you connect a powered ribbon cable, the connector pins can be momentarily misaligned, causing a short between the backlight supply and ground, which can permanently damage the new screen's driver circuitry. The safe order is to disconnect the battery first, then connect the screen, then power on and test; skipping the battery disconnect turns a routine swap into a high-risk component-frying mistake.
When this WOULD be correct
When replacing a screen on a device where the battery is non-removable and the repair procedure explicitly states to test the new screen before fully securing it, but only after ensuring the device is powered off and disconnected from any power source.
- ✗
Apply adhesive to the frame to secure the new screen
Why it's wrong here
Applying adhesive before the new screen is connected and tested is a premature step that can contaminate the delicate flex connector or seat the display before verifying it works. If the replacement screen is defective or the ribbon cable is not properly aligned, the adhesive will need to be cut away, risking damage to the new LCD and the frame. The correct sequence is to connect the screen, confirm the display and touch function, and only then apply adhesive to permanently secure it.
- ✓
Remove or disconnect the battery
Why this is correct
Disconnecting the battery is a mandatory safety step because it physically removes power from the logic board, ensuring no voltage is present when you mate the new screen's ribbon cable to its connector. If the battery remains connected, even a 'powered off' Android can have standby currents that, when connecting the flex cable, can short adjacent pins and send a surge through the backlight or driver IC, frying the new screen. This step also prevents accidental power-on during the repair and is especially critical on devices where the display connector sits near the battery.
- ✗
Update the smartphone's firmware to the latest version
Why it's wrong here
Updating the smartphone's firmware has no bearing on the physical replacement of a cracked LCD—a torn display cannot be fixed by software, and an update will not help install the new hardware. Doing a firmware update during the repair process is counterproductive: it takes time, and if the device is still partly disassembled and the power is interrupted, the update could corrupt the bootloader and make the phone unbootable. If an update is ever needed for display-related bug fixes, it should only be performed after the new screen is installed and the device is fully reassembled.
When this WOULD be correct
A technician is troubleshooting a smartphone that exhibits display glitches, touch unresponsiveness, or boot loops, and the manufacturer's release notes indicate that a firmware update addresses these issues. In that scenario, updating firmware is the correct first step.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 220-1101 exam frequently reuses these exact scenarios with slightly different constraints.
✓Remove or disconnect the batteryCorrect answer▾
Why this is correct
Disconnecting the battery is a mandatory safety step because it physically removes power from the logic board, ensuring no voltage is present when you mate the new screen's ribbon cable to its connector. If the battery remains connected, even a 'powered off' Android can have standby currents that, when connecting the flex cable, can short adjacent pins and send a surge through the backlight or driver IC, frying the new screen. This step also prevents accidental power-on during the repair and is especially critical on devices where the display connector sits near the battery.
✗Connect the new screen and test the display immediatelyWrong answer — click to see why▾
Why this is wrong here
Connecting and testing the new screen immediately risks short-circuiting the display or damaging the phone's motherboard if the battery is still connected, as power may still be present.
★ When this WOULD be the correct answer
When replacing a screen on a device where the battery is non-removable and the repair procedure explicitly states to test the new screen before fully securing it, but only after ensuring the device is powered off and disconnected from any power source.
Why candidates choose this
Candidates may think testing the new screen right away is efficient to confirm it works before final assembly, overlooking the safety step of disconnecting power.
✗Update the smartphone's firmware to the latest versionWrong answer — click to see why▾
Why this is wrong here
Updating firmware is unrelated to hardware repair; the immediate priority after disconnecting the old screen is to ensure the device is powered off to prevent short circuits or damage during installation.
★ When this WOULD be the correct answer
A technician is troubleshooting a smartphone that exhibits display glitches, touch unresponsiveness, or boot loops, and the manufacturer's release notes indicate that a firmware update addresses these issues. In that scenario, updating firmware is the correct first step.
Why candidates choose this
Candidates may mistakenly think that software updates are a universal fix for hardware problems, or they may confuse the repair process with general maintenance procedures.
Analysis generated from the official 220-1101blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.