When something on your phone looks wrong.
Each guide takes one symptom and walks through what to check, in what order, and what the result does and does not prove.

How to test an Android touchscreen for unresponsive areas
A missed touch is hard to judge on its own. A simple drawing test shows whether the gap keeps appearing in the same part of the screen.
Android microphone not working: how to narrow down the problem
Separate recording problems from call problems first. A phone that cannot record your voice needs a different check from one that fails only on calls.
Android camera not working: what to check before a repair
Name the point where the camera fails first. A black preview, a dead shutter, a photo that won't save and a blurry image lead to different checks.
How to document an intermittent problem on an Android phone
An intermittent problem can disappear before anyone else sees it. A short record of what you were doing and what happened gives support a pattern.
Battery health says good on Android: what does it mean?
Good is a status category, not a percentage of original capacity. It also does not tell you how long the next charge will last.
Android screen goes black during calls: normal behavior or a problem?
A screen that goes dark at your ear is working as expected. The useful question is whether it returns reliably when the phone leaves your face.
Android phone charges from a computer but won't transfer files
Charging only proves that power reaches the phone. File transfer also needs a data-capable cable, the right USB mode and a computer that sees the connection.
Android says "No SIM": what to check
Start with the exact message and what happened just before it. During a new phone or eSIM setup, No SIM raises an activation question first.
Auto-rotate is on, but the Android screen won't turn
Start with a screen you know can rotate. The Home screen and portrait-only apps can stay upright even when auto-rotate works everywhere else.
Why has the Android screen turned black and white?
If color disappears each evening, check scheduled features such as Bedtime mode. If it stays black and white all day, look at Color correction.
How to protect your data before an Android phone repair
Before a repair, make a recoverable copy of important data and limit access to your personal information. A repair mode helps with privacy but is no backup.
Android flashlight unavailable: what to check
A missing Flashlight tile, a button that won't switch on and a gray slider are different symptoms. Start with the phone's built-in flashlight control.