How to Check Xiaomi’s Marriage Phone: A Complete Guide with Tests and Tips

Buying a Xiaomi smartphone is always a risk of a factory defect, especially if it comes to models from informal sales channels or used devices. According to service centers, up to 12% of new devices have hidden defects that manifest themselves after 1-3 months of operation, but most problems can be detected before payment, if you know what to pay attention to and what tests to conduct.

In this article, a unique checklist of 17 checks that will help to identify the defect of Redmi, POCO or Mi in 15 minutes, we will analyze not only obvious defects (scratches, broken pixels), but also hidden problems: unstable operation of the NFC module, overheating of the processor, battery fatigue after 100 charging cycles, and also teach you to distinguish the original Xiaomi from a fake by 5 key features.

Important: the instruction is relevant for all models of 2018-2026, including flagships (Xiaomi 14 Ultra), budget (Redmi Note 13) and gaming smartphones (POCO F6 Pro).

1.External examination: 5 signs of marriage that can be seen with the naked eye

Start by visually checking the body and screen, and even small scratches on a metal frame can indicate a fall, and uneven gaps between the screen and the body can indicate improper assembly at the factory.

• 🔍 Screen and frame gaps – if they are wider than 0.3 mm or uneven, this is a sign of build defect. AMOLED-screens (e.g. Xiaomi) 13T Pro) where the slightest displacement may cause damage to the plume.
• 🎨 Uneven coloring of the case – on the original Xiaomi color transitions (for example, on the Redmi Note 12 Pro)+ If you notice any sharp spots or divorces, you're either a fake or a defective batch.
• 📏 Screen curvature: Put the phone on a flat surface with the screen down. If the corners play or if you have a backlash, it's a defect. OCA-glue (connects sensor and matrix).
• 🔋 Bloating battery - swipe your finger over the back cover. If you feel a bulge (even minimal), and the body "crunch" when pressed - the battery has already degraded and is dangerous.
• 🛠️ Autopsy marks - inspect the screws on the bottom cover (if any) on official devices they are branded Xiaomi engraved, and their slits should not be scratched.

⚠️ Warning: If the seller refuses to remove the protective film from the screen or the case from the case, this is a reason to be wary, often hiding chips, cracks or traces of repairs. In 2023, cases where fraudsters pasted on broken Xiaomi screens “masking” films with an imitation of a working matrix have become more frequent.

Screen test: how to identify broken pixels and matrix defects

The screen is the most expensive component of a smartphone, and defects can cost up to 70% of the cost of repair. Use Xiaomi’s built-in menu or third-party apps like Screen Test (available on Google Play) to check.

1. Monochrome fills: Alternately display white, black, red, green and blue on the screen. On a black background, you can see broken pixels (bright dots), on a white background, you can see backlight spots (yellow or gray divorces).
2. Gradient test: The smooth transition from black to white should be uniform. Stripes or sharp jumps in brightness indicate problems with the black. PWM-adjustment (characteristically for AMOLED-screen).
3. Sensor test: Turn on Touch Test mode in the engineering menu (code ##6484##). Draw your finger across the screen - the line should repeat the trajectory without tearing.

⚠️ Note: Xiaomi with 120Hz screens (for example, POCO F5) If you're scrolling, if you're scrolling, if you see a twitch or a tear in the picture, it's a synchronization defect. LTPO-This marriage is not eliminated programmatically!

View the screen on monochrome fills (RGB+black+white)

Check the sensor for responsiveness in Touch Test mode

Evaluate the uniformity of lighting in a dark room

Test the smoothness of the scroll (for 90/120 Hz displays)

Turning your phone at 45° angles doesn’t have to be a “color inversion”

-->

For models with Always-On Display (Xiaomi 13/14 series), additionally check the function: turn it on in the Screen → Always-on settings and leave it for 5 minutes. If after a while the screen goes out or displays artifacts, this is a marriage of the power controller matrix.

Battery Check: How to Find Out the Real Wear of the Battery

The battery is the second most vulnerable component after the screen, and even in a new phone, it can have hidden wear if the device has been in storage for more than a year.

1. Check the number of charging cycles: Go to Settings → Battery status (on MIUI 14+). If the partition is missing, use the AccuBattery app (showing real capacity and wear in percent). Norm for a new phone: 0-5 cycles, 100% health. If the cycles are more than 50, the battery will last less than a year.
2. Discharge test: Charge your phone to 100% and turn off charging. Turn on Plane Mode and play YouTube videos at full brightness. Normal flow: 5-8% per hour for the first time. AMOLED-screens, 8-12% for the IPS. If more, the battery is degraded.

⚠️ Note: Xiaomi with support for fast charging (33W/67W/120W) Check the battery's heating while charging. 40°C (can be checked by infrared thermometer or appendix) AIDA64) — This is a sign of a power controller malfunction, and this defect causes the battery to bloat.

💡

If the seller claims that the phone is “new but was in stock,” ask for a check or production date details. Xiaomi batteries lose up to 20% of capacity in 2 years of storage without recharging.

Camera Diagnostics: How to Identify Module Failure and Program Limitations

Xiaomi cameras often suffer from two problems: hardware defects (blurring, spots on the pictures) and software limitations (disabled features in the firmware for some regions).

• 📸 Test of the main module: Take a photo of text from a distance of 30 cm If the letters "float" along the edges - this is a defect of autofocus (characteristic of the Redmi Note 12 Pro).+ You can shoot a video in a 200MP camera. 4K If you have a lane or a flicker, you're a matrice failure or a problem with a light. ISP-processor.
• 🔦 Flash Check: Enable flash in manual mode (Professional Mode) → Outbreak. → If the light is flashing unevenly or is yellow, the flash driver capacitor is defective.
• 🌌 Night mode test: Take a picture in complete darkness with Night Mode on. The screen should not be green or purple spots - this is a sign of marriage IR-filter.

⚠️ Note: On some models (POCO X5 Pro, Redmi K60) in the firmware for Russia and Europe disabled functions like 8K-Video or Pro mode in the camera. To check for them, go to the camera settings. → If there are no options, it's not marriage, it's a regional constraint that can only be circumvented by flashing.

5.Iron testing: processor, memory and sensors

The iron marriage doesn't show up immediately, but it can make the phone unusable. Use the AIDA64 (free) app to diagnose and follow the instructions:

1. CPU check: Run the CPU Throttling Test in AIDA64. If the CPU frequency drops below 70% of the maximum (for example, the Snapdragon 8 Gen 2 in the Xiaomi 13 Pro should hold 3.2 GHz) - this is a sign of overheating or defective thermal paste.

For models with an infrared port (Redmi Note 11 and older), check it through the Mi Remote app. If the remote does not recognize signals, you may break contacts on the motherboard.

💡

If the Xiaomi phone overheats without load (for example, in the menu), it can be not only a defect of the thermal paste, but also a defect. PMIC-Controller (found on Snapdragon) 7xx This repair costs 30-50% of the cost of the device.

6.Telecommunication Verification: Wi-Fi, Bluetooth, NFC and Mobile Network

Communication problems often occur after purchase, when it is difficult to return the phone under warranty.

• 📶 Mobile Network: Insert two SIM-maps (if supported) and check for VoLTE and 4G/5G. If the internet speed is lower 50 Mbit/s in the coverage area 5G — Modem chip may fail (Redmi has a common problem) 10 2022).
• 📡 Wi-Fi and Bluetooth: Connect to 5 GHz. If the speed is below 300 Mbps, the Wi-Fi 6 module is broken. Pass the file over Bluetooth to another device. If the speed is below 5 MB/s, the controller is defective. BCM43xx.
• 💳 NFC: Try paying for something via Google Pay or attaching your phone to the terminal. NFC does not work the first time or requires a "specific" position - antenna defect (often found after falls).

⚠️ Note: On some models (Xiaomi) 12T, POCO X4 Pro) in firmware for Russia disabled support 5G To test this, type the command in the engineering menu:

AT+QENG="servingcell"

If the answer is not NR5G, your phone does not support 5G in Russia, even if it is stated in the specs.

7.How to distinguish the original Xiaomi from a fake

Xiaomi fakes are almost indistinguishable from the originals, but have critical flaws: weak processors, poor-quality screens and left-handed firmware with viruses.

1. IMEI check: Dial *#06# and compare the number to the battery sticker. Check the IMEI on IMEI.info. If the model doesn't match the one you're looking at, it's a fake.
2. Firmware and menu: The original Xiaomi in Settings → The phone has an exact model number (e.g. 2304FPCD8G for the Redmi Note 12 Pro+).If you see generic names like “Android Phone” instead, it’s a fake.
3. Packaging quality: The original Xiaomi box has a laser engraving of the logo, not a sticker.The package must necessarily include a silicone case (even in budget models) and documentation in Chinese/English.

⚠️ Warning: Counterfeiting is often sold under the guise of "global versions" The original global firmware is labelled MIUI Global in settings, not MIUI China or Custom ROM. It is impossible to reflash the fake on the official software - this will lead to a "brick" (complete inoperability).

FAQ: Frequent questions about Xiaomi marriage