# Step 4: Re-apply normal bias set_source_voltage(channel, V_ACTIVE, pulse_width=10)
The Samsung Galaxy Diagnostics tool is a built-in feature that allows users to test and troubleshoot various aspects of their device, including the screen, battery, sensors, and more. This tool is designed to help users identify potential issues with their device and, in some cases, even fix them without the need for external assistance.
"You’re fixing it, right?" Jara asked.
If you own a Samsung Galaxy device, you’ve probably heard whispers about a secret menu—a hidden laboratory inside your phone where you can test sensors, calibrate the touchscreen, and check the health of your battery.
The SDS tells the user what is wrong (e.g., "Black spot at (x,y)") but offers no fix . A "Hot Fixer" adds a third state: Detect → Classify → Attempt Hot Repair .