How to check the performance of Xiaomi phone: from the screen to the battery

Buying a used Xiaomi smartphone or checking your own device for hidden defects requires a systematic approach. Even a seemingly serviceable phone can hide problems with the battery, communication module or sensors that will manifest themselves in a month of active use. In this article, we will discuss professional methods for diagnosing all key components of Xiaomi, from testing the display for broken pixels to checking the performance of the processor under load.

Particular attention will be paid to hidden faults that are often missed on surface inspection: battery degradation after 500 charging cycles, unstable operation. GPS In urban environments, or in low-light camera artifacts, all tests can be done without any special equipment, but there are enough standard applications and service codes. MIUI.

If you are planning to sell your Xiaomi, this guide will help you to create an honest description of the real state of the device. POCO F5) We have prepared a checklist of critical checks that will protect from buying a cat in a bag".

1. External inspection: what gives negligent treatment

Start with visual diagnostics of the case and screen, and microcracks on the glass are often masked with protective film, so you can look at the device from different angles in good lighting.

• 🔍 Screen frame: glue traces or uneven gaps indicate a replacement display (a common problem after the Xiaomi 13 Lite crashes)
• 📱 Buttons: Check the movement of the volume and power keys - they should not "wake" or fall through
• 🔌 Type-C connector: bend the cable when connected – if the charge is in only one position, the contacts are worn out
• 📶 Antenna lines: scratches on metal body inserts can degrade the signal 5G

Test the vibration output — turn on silent mode and call the phone. Weak vibration or no vibration may indicate motor damage (typical for the mobile phone). POCO X3 Pro after moisture is injected. Don't ignore the smell of the speakers or the charger connector is a sign of short circuit.

⚠️ Warning: If there are traces of corrosion around the screws or under the tray SIM-The cards, the phone was in contact with the liquid, and even after drying, these devices often fail through the air. 3-6 months.

Screen Diagnostics: Broken Pixel Test and Sensor

To check the display, use the service menu MIUI. Go to Settings. → The phone. → Version. MIUI And you tap 5 times on the "Core" line. CIST (or MTK Engineer Mode for MediaTek processors, where select:

Test → Display → Color Test

The monochrome screensavers (red, green, blue, black, white) will be displayed in turn.

• 🖥️ Broken pixels: bright dots on a black background or dark on a white

For a multi-touch test, download the Touch Screen Test app from Google Play. 5 All lines should be smooth, without tears. on Xiaomi with refresh rate 120/144 Hz (Redmi) K60) Check the smoothness of the scroll in the display settings.

View the screen for broken pixels|Test the multi-touch sensor|Check the uniformity of the lighting|Make sure there is no yellowness at the edges-->

3. Battery Testing: How to Find Out Real Wear

Battery capacity is a key parameter when buying used Xiaomi. Even if the phone is "normally charged," the actual wear and tear can exceed 30%.

1. Install the AccuBattery app (shows real capacity in mAh)
2. Go to Settings. → Battery → Battery status (some models display percentage of wear)
3. For Xiaomi, enter the code ##4636 on Qualcomm## →"Battery information"

Compare the data obtained with passport values:

The critical indicator is the discharge rate in standby mode. 10-15% overnight with Wi-Fi and mobile data turned off, it is a sign of either a worn-out battery or background malware activity.

⚠️ Note: On Xiaomi with fast charging (67W/120W) Check the temperature of the case while charging. 45°C (can be checked in AIDA64), This speeds up the degradation of the battery in 2-3 once.

4. Camera inspection: how to detect software and hardware defects

Xiaomi camera modules often suffer from software limitations (e.g., switched off) 4K on budget models) or hardware defects (edge blur, artifacts with zoom:

• 📸 Test of all modules: open the standard camera application and alternately check: Main module (resolution, focus) Wide-angle (edge distortion) Macro lens (minimum focal length) Front camera (noise in the dark)
• 🔦 Shooting in different conditions: In bright light (relights, chromatic aberrations) In the dark (noise level on the ground) ISO 3200+) Video 4K@60fps (hull heating, braking)

For a deep diagnosis, use Camera. MX Manual Camera – They show the real-world capabilities of the sensor without processing. MIUI. Pay attention to this:

• 🎯 Autofocus: should be triggered by 0.3-0.5 Slowing down indicates lens contamination or motor malfunction
• 🌈 Color rendering: compare the photo with reference (for example, a piece of white paper should be white, not yellow)
• 📏 Distortion: On the wide-angle module, check straight lines along the edges of the frame (they should not "close down")

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If the Xiaomi camera gives an error “I failed to connect”, try resetting the camera settings in Settings → Annexes → Camera. → Warehouse → Clear the data. If it doesn't work, the plume or the module is broken.

5. Productivity diagnostics: CPU, GPU memory

Slowdowns and lags on Xiaomi may be caused as software restrictions MIUI (background optimization, and hardware problems (chipset overheating, flash memory wear:

1. Install AnTuTu Benchmark or Geekbench 6 – compare the results with the reference for your model (the data is available on GSMArena).
2. Check the trolling (reduced frequency when heated) in CPU Throttling Test

Critical symptoms of malfunction:

• 🔥 Overheating over 70°C scoring tasks (e.g. Redmi 10 on Snapdragon 680 should not heat above 60)°C in PUBG Mobile)
• 🐢 Subsidence FPS post-game 10-15 minutes (typical of the POCO X3 Pro with worn-out thermopaste)
• 💾 Slow recording/reading of memory (checked in the AIDA64 →"Warehouse")

For Xiaomi on MediaTek (e.g. Redmi Note) 12) Pay special attention to the test eMMC/UFS. If the reading speed is lower 200 MB/s, flash memory has degraded and needs to be replaced.

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If the difference between your result and the reference is more than 20% in AnTuTu, it is a sign of either thermal throttling or component failure.

6.Contact check: Wi-Fi, mobile network and GPS

Communication problems on Xiaomi are often selective – for example, Wi-Fi works, but the problem is not. 5G no, or GPS It only catches satellites in open areas:

• 📶 Mobile Network: Check support for all bands 4G/5G In Settings → SIM-maps and mobile networks → Network settings Speedtest.net (should meet the tariff) Call the phone from another number - there should be no noise or breaks
• 🟓 GPS: Use GPSTest to check the number of satellites (in the city the norm — 8-12, open-air — 15+) Compare coordinates with Google Maps (the deviation should not exceed) 10 )

Typical malfunctions:

⚠️ Attention: Xiaomi with two SIM-Cards (Redmi Note 11 Pro)+) Check both sims at the same time, and if one of them is periodically missing, it could be a hardware defect in the communications module.

7. Testing of sensors and additional functions

Xiaomi is equipped with a lot of sensors, the failure of which is not always noticeable immediately. VR-And the appendix, and the rogue proximity sensor will turn off the screen when you call it:

1. Open Sensor Test from Google Play or type in the dial number: ##6484## (for Qualcomm sensor test)
2. Check the reaction to movements: Accelerometer (tilts of the phone), Gyroscope (rotation in space) Compass (coincidence with real north)

biometrics

• Fingerprint scanner (must work with 1 try in 90% of cases)
• Facial recognition (check in the dark – the IR camera must work)

Pay particular attention to:

• 🔦 Light sensor: automatic brightness control should work smoothly
• 🎤 Microphones: Record voice from different distances (Xiaomi often refuses the top microphone for noise reduction)
• 🔋 Contactless charging (if supported): check compatibility with Qi charges 15W+

Nana POCO F4 GT Test trigger buttons (if any) – they should be triggered without delay in games such as Call of Duty Mobile.

8.Service codes and hidden menus for deep diagnostics

The manufacturer hides a number of tests available through engineering codes that allow hardware components to be tested at the firmware level.

For models on MediaTek (Redmi) 10C, POCO M5) Use ##36446337## to open an extended engineering menu with camera, audio and communication module tests.

⚠️ Warning: Do not change the settings in the engineering menu if you do not understand their purpose! LTE It can lead to the loss of the network.

If after entering the code, a message appears "Connection with the server is interrupted", this means that:

• The firmware has been modified (custom recavery installed)
• The phone is blocked by the operator (for example, Xiaomi for MegaFon)
• No code support for your model/region

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Service codes work only on standard firmware MIUI. On custom. ROM (For example, LineageOS, most of them will not be available.

FAQ: Answers to Frequent Questions