Phone Diagnostic Checklist

Open any app. Slowly drag your finger across the entire screen — top to bottom and left to right. Watch for: any spot the screen does not respond to your touch, dead pixels (small black dots that never light up), color streaks, or cracked areas where touch fails.

Open YouTube or a music app. Play any video or song. Set the phone face-up on a table without covering the bottom edge. Slowly increase the volume to maximum. Listen for: any rattling, distortion, dropouts, or one-sided sound. The sound should be clear and equal in volume from all sides of the speaker grille.

Open the Voice Memos app (iPhone) or Voice Recorder (Android). Record yourself saying "The weather today is sunny and seventy-two degrees" at normal speaking volume. Play the recording back. Listen for: muffled sound, missing words, or complete silence.

Open the Camera app (rear camera, the regular setting). Take a photo of a brightly lit, detailed scene — a window, a houseplant, or text on paper. Look at the photo: is it sharp and clear, or blurry, foggy, or showing spots and streaks?

Switch to the front-facing (selfie) camera. Take a photo of yourself in well-lit conditions. The photo should be sharp and properly exposed.

Lock the phone (press the side button). Pick up the phone and look at it as you normally would. The phone should unlock within 1–2 seconds without you doing anything else. If your phone uses fingerprint instead of face, test the fingerprint sensor on the front, back, or side instead.

Plug your phone into a charger using your normal cable. The phone should immediately show a charging icon. The cable should fit snugly in the charging port — not loose, not requiring you to hold it at a strange angle.

Open Settings → WiFi. The list of nearby networks should appear within a few seconds and include networks you can see other devices using. Connect to your home WiFi. Open a web browser and load any website.

Open Maps (Apple Maps or Google Maps). Tap the location button (a small target icon, usually bottom-right). The map should center on your actual location within 10–30 seconds. The blue dot should be on or very near your house, not several blocks away.

Settings → Sounds & Haptics (iPhone) or Sounds and vibration (Android). Find the vibration test or set the phone to silent mode and call yourself from a landline or another phone. The phone should vibrate noticeably.

Press the volume up button. The volume indicator should appear and rise on screen. Press volume down — it should fall. Press the side (power) button — the screen should turn off and on. Test any other physical buttons (mute switch, action button).