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How to check a phone or laptop after a repair

Updated September 27, 2026

After a screen, battery or board repair, a device can look fine while the faults hide where you don't look: a crackly earpiece, a proximity sensor that no longer turns the screen off during calls, Face ID gone, or a replacement screen stuck at 60 Hz. This guide gets you through a check in about 10 minutes at the shop, before you pay, while it's still easy to ask for a fix.

Tip: if you saved a Soi Máy report before the repair, run the tests again and compare the two reports. Anything that passed before and fails now was caused by this repair.

1. Ask before you collect it

  • Which parts were replaced and what kind: original, pulled from another device, or aftermarket (a cheaper screen, a "high-capacity" battery…).
  • How long the warranty is, what it covers, and whether it's written on the receipt.
  • Ask for the old parts back if you want them, and for a receipt with the device's IMEI or serial number.

2. The screen after a replacement

Cheap replacement screens are often dimmer, tinted (yellowish or bluish), with narrower viewing angles, or an LCD fitted in place of the original OLED (greyish blacks, thicker borders). Set brightness to maximum and step through the colours:

Dead pixel, backlight bleed and burn-in testFind dead or stuck pixels, backlight bleed, burn-in and lines on a phone or laptop screen. Eight full-screen colours, free, no app to install.
  • White: look for a yellow tint, blotches or dark spots.
  • Black in a dark room: an original OLED is perfectly black; a grey glow or light bleed means an LCD replacement.
  • If the device has a 90 or 120 Hz screen, measure the refresh rate again: many replacement screens only run at 60 Hz.
  • iPhone: check True Tone can still be turned on in Control Center; many non-original screens lose it.

3. Touch and the sensors around the screen

After a screen swap, touch can die in one area or produce ghost touches. Fill the whole grid:

Touch screen test: dead zones and ghost touchesSwipe to fill a grid of cells and spot dead touch zones or ghost touches on a phone or tablet. Runs full screen, free.

Then check the parts right next to the screen, which are easy to disturb:

  • Proximity sensor: make a call and hold the phone to your ear; the screen must turn off, and come back when you move it away.
  • Auto-brightness: turn it on and cover the sensor above the screen; brightness should drop.
  • In-display fingerprint: enroll a new fingerprint. Non-original screens often break it.
  • Face ID (iPhone): add an alternate appearance in Settings. The front sensor cable is easy to damage during a screen swap. Try it with the biometric test.

4. Earpiece, microphones, front camera

The earpiece and front camera usually have to be moved to the new screen:

  • Make a call and listen through the earpiece: loud, clear, no crackle. The speaker test plays the top and bottom speakers separately.
  • Record and play back with the mic test.
  • Open the front camera: no haze, streaks or dust inside. Use the camera test.

5. After a battery replacement

  • iPhone: check Settings › Battery › Battery Health. A new genuine battery shows close to 100%. A non-genuine one usually shows "Unknown" or a message that the battery can't be verified. That's expected for an aftermarket battery, but you should know which kind you got.
  • Android: check Samsung Members or Settings › Battery (depending on the phone).
  • Look along the edges: the screen must sit flush all round, with no glue gap and no side lifting.
  • Plug in a charger: it should start charging at once and not get unusually hot. The battery test flags every plug and unplug and measures the drain rate.
Battery and charging port testSee the battery level, detect plugging and unplugging to test a loose charging port, and watch how fast the battery drains. Plus how to read battery health on iPhone, Android and laptops.

6. Signal, Wi-Fi, buttons, vibration

Opening a phone means touching the antennas and button cables:

  • Check signal bars, make a call on your SIM, turn on Wi-Fi and Bluetooth.
  • Press power and volume and flip the silent switch: they must click and work.
  • Make sure it vibrates for calls and notifications.

7. Laptops after a repair

  • Keyboard and touchpad: often affected by battery swaps or cleaning. Run the keyboard and touchpad tests.
  • Fans and temperature: run the CPU test for a few minutes; the fan should be smooth and the laptop not too hot.
  • Ports, Wi-Fi, webcam, speakers: try each one.
  • Screws underneath all present, bottom cover flush.

8. Water resistance

Once a phone has been opened, its water resistance is mostly gone unless the shop fitted a new, proper seal. Ask whether they did, and be more careful with water from now on.

When you're done

Save the results as a PDF or a link and QR code on the soimay.com Results page and keep it with the repair receipt. If a fault appears a few days later, you have a record of the device's condition when you collected it.

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