Uploaded August 2026 | Updated September 2026, 2 weeks ago
How to Test Any Samsung Galaxy Phone for Dead Pixels and Dead Touch Zones
If you're buying a used, refurbished, or renewed Samsung Galaxy phone, it's a good idea to test both the display and the touchscreen before the return window expires.
Method 1: Test for Dead Touch Zones (Works on Most Galaxy Phones)
Step 1: Enable Developer Options
Open Settings.
Tap About phone.
Tap Software information.
Tap Build number 7 times.
Enter your PIN if prompted.
You'll see "Developer mode has been enabled."
Step 2: Turn On Pointer Location
Go back to Settings.
Open Developer options.
Turn on Pointer location.
A crosshair and touch trail will appear on the screen.
Step 3: Test the Entire Screen
Without lifting your finger:
Draw horizontal lines.
Draw vertical lines.
Draw diagonal lines.
Draw circles around the edges.
What to Look For
A healthy touchscreen will:
Produce one continuous line.
Follow your finger smoothly.
Respond everywhere on the screen.
A defective touchscreen may:
Stop drawing in one area.
Skip across a strip.
Lose tracking.
Show a vertical or horizontal dead zone.
A dead strip that appears in the same place every time usually indicates a faulty digitizer.
Method 2: Samsung's Built-In Touch Test
Many Samsung Galaxy phones also include a hidden hardware diagnostic menu.
Open the Phone app.
Dial:
*#0*#
Tap Touch.
Trace every square on the grid.
If every square changes color, the touchscreen is functioning properly.
Note: Some U.S. carrier models disable this diagnostic menu.
Method 3: Check for Dead Pixels
Dead pixels are different from touch problems.
A dead pixel:
Appears as a tiny black, white, red, green, or blue dot.
Still responds to touch.
Doesn't change color when the screen changes.
How to Test
Increase screen brightness to maximum.
Open full-screen solid color images:
White
Black
Red
Green
Blue
Carefully inspect the display.
If a tiny dot remains the same color on every screen, it's likely a dead or stuck pixel.
You can also use a free dead pixel test app from the Google Play Store to display these colors.
Additional Checks
While testing a Galaxy phone, also verify:
Speakers
Microphones
Cameras
Flashlight
Wi-Fi
Bluetooth
Cellular signal
Charging port
Fingerprint reader
Power and volume buttons
Vibration motor
Pro Tip for Buying Refurbished Phones
If you're buying a renewed or used Samsung Galaxy phone, perform these tests before transferring your data. It's much easier to return or exchange a defective phone while it's still in its return window than after you've spent time setting it up. #samsunggalaxy
Disclaimer: As an Amazon Associate I earn from qualified purchases.
How to Test Any Samsung Galaxy Phone for Dead Pixels and Dead Touch Zones
If you're buying a used, refurbished, or renewed Samsung Galaxy phone, it's a good idea to test both the display and the touchscreen before the return window expires.
Method 1: Test for Dead Touch Zones (Works on Most Galaxy Phones)
Step 1: Enable Developer Options
Open Settings.
Tap About phone.
Tap Software information.
Tap Build number 7 times.
Enter your PIN if prompted.
You'll see "Developer mode has been enabled."
Step 2: Turn On Pointer Location
Go back to Settings.
Open Developer options.
Turn on Pointer location.
A crosshair and touch trail will appear on the screen.
Step 3: Test the Entire Screen
Without lifting your finger:
Draw horizontal lines.
Draw vertical lines.
Draw diagonal lines.
Draw circles around the edges.
What to Look For
A healthy touchscreen will:
Produce one continuous line.
Follow your finger smoothly.
Respond everywhere on the screen.
A defective touchscreen may:
Stop drawing in one area.
Skip across a strip.
Lose tracking.
Show a vertical or horizontal dead zone.
A dead strip that appears in the same place every time usually indicates a faulty digitizer.
Method 2: Samsung's Built-In Touch Test
Many Samsung Galaxy phones also include a hidden hardware diagnostic menu.
Open the Phone app.
Dial:
*#0*#
Tap Touch.
Trace every square on the grid.
If every square changes color, the touchscreen is functioning properly.
Note: Some U.S. carrier models disable this diagnostic menu.
Method 3: Check for Dead Pixels
Dead pixels are different from touch problems.
A dead pixel:
Appears as a tiny black, white, red, green, or blue dot.
Still responds to touch.
Doesn't change color when the screen changes.
How to Test
Increase screen brightness to maximum.
Open full-screen solid color images:
White
Black
Red
Green
Blue
Carefully inspect the display.
If a tiny dot remains the same color on every screen, it's likely a dead or stuck pixel.
You can also use a free dead pixel test app from the Google Play Store to display these colors.
Additional Checks
While testing a Galaxy phone, also verify:
Speakers
Microphones
Cameras
Flashlight
Wi-Fi
Bluetooth
Cellular signal
Charging port
Fingerprint reader
Power and volume buttons
Vibration motor
Pro Tip for Buying Refurbished Phones
If you're buying a renewed or used Samsung Galaxy phone, perform these tests before transferring your data. It's much easier to return or exchange a defective phone while it's still in its return window than after you've spent time setting it up. #samsunggalaxy
Disclaimer: As an Amazon Associate I earn from qualified purchases.
