Laptop keyboard disconnected but still sending input?

Understanding and Troubleshooting Keyboard Input Issues on Laptops: A Case Study with Acer Nitro Series

Introduction

Laptop keyboard malfunctions can be both perplexing and disruptive, especially when standard troubleshooting steps do not resolve the issue. In this article, we explore a real-world scenario involving an Acer Nitro laptop experiencing persistent key input problems, despite the physical keyboard being disconnected. Such cases highlight the importance of understanding how keyboard inputs are processed and where potential faults may occur.

Case Overview

The user reports that their Acer Nitro laptop’s keyboard exhibited intermittent malfunctioning over a six-month period. Notably, the ‘D’ key would sometimes fail to register presses and, at other times, would falsely indicate it was being pressed. To mitigate this, the user opted to use an external, standalone keyboard, which functioned correctly without issues.

Recently, the problem escalated: the Windows key (Win) began registering as pressed repeatedly and unpredictably. This behavior affected system navigation, causing windows to minimize unexpectedly, notably when combined with other key presses such as ‘D’.

Troubleshooting Attempts

The user attempted several troubleshooting measures, including:

Disconnecting the external keyboard to determine if it was the source of false inputs.
Activating the on-screen keyboard to verify whether the problem persisted without physical keyboards connected.

Despite these efforts, the issue persisted. Their boyfriend even disassembled the laptop and disconnected the internal keyboard, expecting this to resolve the false keypresses. Surprisingly, the system continued to register these keys as pressed, even with all physical input devices disconnected.

Possible Causes and Diagnostic Considerations

This scenario suggests that the problem might not be solely hardware-based. Some potential causes include:

Ghost Keypresses or Software Glitches:
Certain keyboard issues can originate from driver corruption, background processes, or system anomalies that cause phantom key events.
Input Device Emulation or Hardware Faults:
The internal keyboard matrix or connection points might be damaged, leading the system to misinterpret signals.
Embedded Controller or Firmware Issues:
Malfunctions within the keyboard controller or firmware could erroneously send signals to the operating system, independent of physical keys.
Malware or Background Processes:
Although less common, malicious software or errant processes can simulate keyboard inputs.