How to check a phone screen and touchscreen

Start with a controlled check

Clean and dry the screen, remove gloves, and use comfortable brightness in even room lighting. Inspect the glass with the screen off before running a display test. Note cracks, marks and areas hidden by a case. Do not press harder on a suspicious spot.

Inspect colours and coverage

Open the screen test and inspect each solid colour. Look for a spot that stays different from its surroundings across several colours. A mark on the glass can resemble a pixel problem, so compare it with the screen off. Record where the symptom appears rather than labelling every dot a dead pixel.

In the touch test, slowly trace across the entire grid, including edges and corners. Lift your finger and repeat any missed area from another direction. A fast swipe can skip a cell; one missed square alone is not a diagnosis.

Check more than one contact

Open the multitouch test. Place two fingers inside the pad, then move them separately while keeping contact. Add fingers gradually if practical. Watch whether the markers follow each contact and whether the observed count drops unexpectedly. The highest count you reach is the count observed in that session, not a certified hardware maximum. Browser gestures and the size of the pad can limit the test.

Interpret and repeat

A repeatable gap at the same physical position is worth further investigation. Repeat in the phone’s own interface or a manufacturer diagnostic, where available. If the problem only happens on one website, record that distinction. Mark Working only for what you actually observed; use Issue for a repeatable unexpected result and skip anything you could not assess.

What this does not establish

These checks do not identify the cause of a damaged display, measure colour calibration or certify the quality of a replacement panel. Persistent symptoms need a separate assessment before repair decisions.