How to check Xiaomi Mi Band 4: full diagnostic manual

Buying a used gadget or checking a device after a long downtime is always a risk of encountering hidden defects that are not visible on a cursory inspection. Xiaomi’s Mi Band series fitness bracelets have proven to be reliable assistants, but even they can encounter factory defects or the consequences of careless use. Competent diagnosis allows you to identify problems with the display, pulsemeter or battery before they become critical.

In this article, we will take a detailed look at all the steps of the Xiaomi Mi Band 4 verification, including the use of hidden engineering menus and third-party applications. You do not need to be an expert in electronics to conduct a basic test drive of the device.

External inspection and configuration check

The first thing that any electronics check starts with is a thorough visual analysis of the body and strap.The tracker should not have deep scratches, chips or cracks, especially in the area of the screen, as they can develop into serious damage to the matrix.Inspect the contacts for charging on the tracker itself: they should be clean, without traces of oxidation or corrosion, which often occurs after wearing in the pool or shower.

Pay attention to the integrity of the silicone strap. Rubber products lose elasticity over time and can crack at the folding sites, which will lead to the loss of the device during training. Make sure that the capsule (the main unit) sits tightly in the pad and does not hang, as this can lead to loss when active movement.

• 👁️ Check the screen for broken pixels when turning on the white background.
• 🔌 Make sure that the charging contacts do not have black plaque.
• 🧶 Check the strap for microcracks at the base.

⚠️ Warning: If you notice a bloating capsule or deformation of the body, in no case do not try to charge the device - this can lead to a fire of the lithium battery.

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Before buying a used device, be sure to smell the strap - the sharp smell of cheap silicone or chemistry often indicates the replacement of the original accessory with a poor-quality copy.

Checking the display and touch screen

The screen is the most vulnerable element of the Mi Band 4 design. For a qualitative check, you need to turn on the device and carefully consider the image for uneven backlight or color spots. AMOLED-The matrix installed in this model should show deep black and saturated shades; if you see a grayish hue on a black background, this may indicate pixel degradation.

Special attention should be paid to the work of the touch layer, which in the fourth version of the bracelet became colored and more sensitive. Swipe your finger across the screen, swiping through the menu: the response should be instantaneous, without delays and "dead zones." Sometimes after a fall, the touch screen begins to work incorrectly at the edges, which can only be detected when you use the interface actively.

For detailed analysis, you can display monochromatic images of different colors, which will help to identify the burnout of individual subpixels, which is characteristic of the pixels. OLED-technologies for long-term operation at high brightness.

• 🎨 Test the display of all the primary colors of the rainbow.
• 👆 Check the reaction to touch in the corners of the screen.
• 💡 Estimate the maximum and minimum brightness of the backlight.

Testing of sensors and health functions

The main task of any fitness tracker is to collect biometric data, so checking the sensors is a critical step.The optical pulsemeter located on the back should fit tightly to the skin and be free of contamination. For the test, put a bracelet on your wrist, run a pulse measurement and compare readings with another tested device or manually count heartbeats in 15 seconds, multiplying the result by four.

You also need to check the accelerometer, which is responsible for counting steps. Walk with the device in your hand about 50-100 steps and see if the counter in the activity menu has increased. If the pedometer is standing still or showing chaotic values, the gyroscope may have failed or the software failure requires flashing.

Be sure to test the sleep monitoring function by leaving the bracelet overnight, and the correct operation of this mode depends on how accurately the sensors detect the stillness and frequency of the pulse in the dark.

⚠️ Note: The pulse sensor can give a significant error if the bracelet is worn too weak or is over the bone of the wrist - always tighten the strap tightly, but without compression.

Battery Diagnosis and Charging

Autonomy is one of the main advantages of Xiaomi Mi Band 4, and the battery condition directly affects the comfort of use. When connected to the charger, the screen should light up almost instantly, and the display display displays charging animations. If the device responds to a connection with a delay or requires a “swing” (long stay on charging before turning on), this is an alarm signal.

During operation, pay attention to the discharge rate. A proper tracker in standby mode with Bluetooth enabled and periodic pulse measurements should work from 10 to 20 days. If the charge goes away in 2-3 days, then the battery capacity has decreased significantly or background errors occur in the system that cause the processor to overheat.

Also check the case heating during charging. Easy heat is acceptable, but if the bracelet gets hot, it indicates problems with the power controller or an internal short circuit.

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A sudden loss of charge (e.g., from 40% to 5% per hour) often indicates a need for battery calibration or replacement.

Waterproofing

The Mi Band 4 is 5 ATM certified, which theoretically allows it to be submerged to a depth of 50 meters. However, when buying a used device, you can not rely on the declared characteristics, since the leakage may have been disturbed by shocks or temperature changes. Visually check the integrity of the gaskets and the absence of gaps between the screen and the body.

It is better to conduct a preliminary test: turn on the "Swimming" mode in the bracelet menu, soak your hands and swipe your finger across the screen to activate the water lock, and then lower your hand into a glass of water for a couple of minutes. After extracting, check if moisture has been hit by the glass and if the touchscreen is working.

Therefore, even a serviceable device requires careful handling in aggressive environments.

• 🏊‍♂️ Activate the “Swimming” mode before contact with water.
• 💧 Wash the device with fresh water after the sea or chlorine.
• 🚫 Avoid getting a jet of water under high pressure (shower, water skiing).

Use of engineering menus and applications

For deep testing, Xiaomi Mi Band 4 can be used hidden features and third-party software. the official Mi Fit app (or Zepp Life) shows basic information, but for detailed diagnostics enthusiasts use special utilities. One popular method is to log into the engineering menu through certain combinations of actions or use modified versions of applications.

There is a popular application "Mi Band". 4-5-6 Tools" (or analogues), which allows you to read raw data from sensors, check the firmware version, MAC-And you can use the address and perform vibration tests, and by connecting the bracelet to this application, you can trigger a forced vibration of varying intensity, which can help you detect the rattling or complete failure of the motor.

Also, third-party software often shows the actual battery wear and recharge cycles, which are key parameters in estimating the residual life of a device, hidden from the average user but available for diagnostic purposes.

Annex discharge procedure:




1. Open the device settings in the application.




2. Find the item "Unbind" or "Unbind".




3. Confirm the action and wait for the reboot.

The table below shows the main parameters that are worth checking and their normal values:

Frequently Asked Questions (FAQ)