220-1101 Question 436
Single answerDigitizer issuesA user brings in a Windows 2-in-1 device and reports that touch input is inaccurate near the edges of the screen. The display looks normal, and the user can open apps with the keyboard and touchpad. The problem started after the device was dropped, and cleaning the screen did not help. Which of the following is the MOST likely cause of the issue?
- A
The LCD backlight is failing and causing touch offset
- B
The digitizer layer is damaged and needs replacement
- C
The Wi-Fi antenna is loose inside the display assembly
- D
The system clock battery is depleted and affecting screen calibration
Show answer and explanation
Correct answer: B
Explanation
This scenario points to a damaged digitizer, not a display-image problem. In many laptops, tablets, and 2-in-1 devices, the LCD or OLED panel can still show a normal picture while the separate touch-sensitive digitizer layer is damaged. Inaccurate or dead touch zones, especially after a drop, are classic symptoms. As part of standard troubleshooting best practices, a technician should first verify the symptom, check for obvious physical damage, and rule out simple causes such as dirt, screen protectors, or calibration settings. However, because the issue began after impact and affects touch accuracy rather than video output, hardware damage to the digitizer is the most likely root cause. This aligns with common manufacturer service guidance for touchscreen assemblies, where the digitizer or full display assembly is replaced if touch input becomes unreliable after physical damage.
- A. Incorrect.
Incorrect. A failing LCD backlight affects screen brightness or causes a dim display, but it does not typically cause touch input to register inaccurately in specific areas. The scenario states that the display appears normal, which further rules out a backlight issue.
- B. Correct.
Correct. The digitizer is the component that detects touch input on a touchscreen device. If touch is inaccurate, especially after physical impact, damage to the digitizer layer is a likely cause. This is a common real-world symptom of a cracked or partially damaged touch-sensing layer, even when the image on the display still looks fine.
- C. Incorrect.
Incorrect. A loose Wi-Fi antenna can cause weak or intermittent wireless connectivity, but it has no role in touch detection accuracy. This is a plausible distractor because the antenna may be routed through the display assembly in some devices, but it would not create edge-specific touch problems.
- D. Incorrect.
Incorrect. A depleted CMOS/RTC battery can cause time and BIOS settings issues on some systems, but it does not affect touchscreen accuracy. Choosing this option would reflect confusion between general hardware faults and the specific hardware responsible for touch input.