Cracked Screen & Touch Unresponsive: Digitizer Failure
A user reports that their smartphone's touch screen is unresponsive. The technician observes that the screen is cracked and has visible black spots. The phone still powers on and the physical buttons work. Which of the following components is MOST likely faulty?
Quick Answer
The answer is the digitizer. This is correct because the digitizer is the transparent layer that converts your finger’s touch into electrical signals the phone can interpret, and a cracked screen with visible black spots indicates physical damage to that layer, directly causing unresponsiveness to touch while the LCD display beneath may still show an image. On the CompTIA A+ Core 1 220-1101 exam, this scenario tests your ability to distinguish between the digitizer and the LCD—a common trap is assuming a cracked screen always means a dead display, but the fact that the phone powers on and physical buttons work points squarely to digitizer failure. Remember the memory tip: “Touch goes to the digitizer, picture goes to the LCD.”
⚠ Common exam trap
CompTIA often tests the misconception that a cracked screen always means the LCD is faulty, leading candidates to select 'LCD display' when the actual failure is in the digitizer layer responsible for touch input.
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
✓
Digitizer
The digitizer is the layer responsible for converting touch input into electrical signals. A cracked screen with visible black spots indicates physical damage to the digitizer layer, which directly causes unresponsiveness to touch. The LCD display may still function (showing an image) even when the digitizer is broken, which matches the symptom of the phone powering on and physical buttons working.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
LCD display
Why it's wrong here
The LCD can still display an image (despite cracks) but would not directly cause touch unresponsiveness. A damaged LCD usually results in display artifacts or no image, not just unresponsive touch.
- ✓
Digitizer
Why this is correct
The digitizer is the touch-sensitive layer that converts touch inputs into signals. Cracks can sever the digitizer's circuits, making the screen unresponsive to touch while the display still works.
- ✗
Battery
Why it's wrong here
A faulty battery could cause unexpected shutdowns or charging issues, but it would not cause the touch screen to become unresponsive while the phone remains powered on.
- ✗
Motherboard
Why it's wrong here
A motherboard failure typically causes more systemic problems such as no power or boot loops. It is unlikely to cause isolated touch unresponsiveness while the phone otherwise functions.
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Same concept, more angles
2 more ways this is tested on 220-1101
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user reports that their smartphone's touchscreen is unresponsive in a small area near the bottom-left corner after dropping the device. The screen is not cracked, and the display still shows images correctly in that area. The technician has already performed a soft reset and verified that no screen protector is interfering. Which of the following is the most likely cause?
medium- ✓ A.A. The digitizer layer is damaged
- B.B. The LCD panel is cracked internally
- C.C. The battery is swollen and pressing against the screen
- D.D. The screen resolution settings are incorrect
Why A: The digitizer layer is the component responsible for detecting touch input. When a smartphone is dropped, the digitizer can sustain localized damage—such as a cracked or delaminated sensor grid—even if the display (LCD/OLED) remains intact and shows images correctly. The unresponsive area in the bottom-left corner, combined with normal image display, points directly to a damaged digitizer rather than the LCD panel.
Variation 2. A user reports that the touchscreen on their smartphone is unresponsive in a vertical strip approximately one inch wide, running from the top to the bottom of the screen. All other areas of the screen respond correctly to touch. The user has cleaned the screen and removed the screen protector. The phone has not been dropped or exposed to liquid. Which of the following components is MOST likely causing this issue?
hard- ✓ A.Digitizer failure
- B.LCD panel failure
- C.Software glitch
- D.Battery swelling
Why A: The digitizer is the layer responsible for detecting touch input. A vertical strip of unresponsiveness, without any impact or liquid damage, indicates a localized failure of the digitizer's grid of electrodes, often caused by a manufacturing defect or internal crack in the digitizer layer itself. The LCD panel remains functional because the display still shows images correctly in that area.
JA
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.