Why the screen on Xiaomi Redmi Note 8T goes off when you call – a full analysis of the causes and solutions

You make a big call, you bring the Xiaomi Redmi Note 8T to your ear, and suddenly the screen goes out, leaving you in the dark: whether the conversation is ongoing, whether the person has heard your words, or the communication has already been interrupted. This problem is familiar to many model owners, and it can unbalance even the patient user. Unlike the random glitches, when the screen goes out once and does not repeat, the system shutdown of the display during calls signals specific problems, both software and hardware.

In this article, we will not just list the possible causes, but analyze them with the unique features of the Redmi Note 8T: from the known bugs of MIUI firmware to the “childhood diseases” of the proximity sensor, which often becomes the culprit, you will get clear diagnostic instructions, step-by-step solutions (including hidden developer settings) and criteria by which you can determine when it is time to bring your phone to the service.

1. Approximation sensor: the main reason for turning off the screen

In 80 percent of cases, the approach sensor, a small infrared sensor next to the front camera, is responsible for detecting when you're holding your phone to your ear and turning off the screen to avoid accidental taps. On the Redmi Note 8T, this sensor often malfunctions because of:

• 🔹 Sensor contamination – dust, greasy prints or protective film block infrared signal.
• 🔹 Software failure - firmware MIUI misinterprets sensor data.
• 🔹 Mechanical damage – after a fall or impact, the sensor may shift or lose calibration.
• 🔹 Conflict with the case - some accessories overlap the range of the sensor.

To check the sensor, use the secret code:

##6484##

Once you enter, the test menu will open, where you will see the status of the Proximity Sensor. Hold your hand to the top of the screen - the value should change from 5.00 cm to 0.00 cm. If the readings do not change or jump randomly - the sensor is defective.

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If the sensor test shows an incorrect value, try restarting the phone and rechecking. Sometimes the failure is temporary and fixed by a simple reboot.

2. MIUI firmware failures: bugs and updates

Xiaomi Redmi Note 8T came with the factory firmware MIUI 10, but many users faced the problem of the fading screen after upgrading to MIUI 11 or MIUI 12.The fact that in these versions changed the logic of processing signals from the proximity sensor, and some devices began to misinterpret the usual conditions as “phone to the ear”.

How it manifests itself:

• 📱 The screen goes off even when the phone is on the table during a conversation.
• 🔄 After the update, the problem appeared “on the level».
• 🔧 Resetting sensor settings in the developer menu does not help.

Decisions:

1. Reverse the firmware to a stable version (e.g. MIUI 10.3.8.0). This requires unlocking the bootloader and using the Mi Flash Tool.
2. Install custom firmware (e.g. Pixel Experience or LineageOS) where the sensor logic is reworked.
3. Waiting for a patch – Xiaomi periodically releases fixes for such bugs (watch out for updates in Settings → About Phone → System Update).

3. Developer settings: hidden sensor parameters

If the proximity sensor is working correctly, but the screen is still going out, the problem may be in the wrong settings of the system. There are parameters in the developer's menu that affect the behavior of the screen during calls.

1. Go to Settings. → The phone.
2. Click 7 times on the MIUI version (you will be notified “You are a developer”).
3. Go back to the main settings menu and open a new section for developers.

Now, find the following parameters and change them:

Disable "Switch off screen when approaching" |Set trigger threshold at 10-12 cm|Check screen shutdown delay |Reset sensor settings to factory

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Note: If after changes to the developer menu, the screen stopped turning off even when you actually approach the ear, return the settings back - this can lead to accidental taps during a conversation.

4. Hardware malfunctions: when the "iron" is to blame

If the software methods didn't work, the problem is the physical breakdown of the components. 8T The following hardware defects are:

• 🔌 Oxidation or dumping of the sensor plume - after moisture or mechanical exposure.
• 🔋 Display module malfunction – the screen may go out due to backlight or controller problems.
• 📶 Poor contact of the antenna module - affects the stability of communication, which indirectly leads to failures during calls.

How to diagnose:

1. Call the plumes with a multimeter (requires disassembly of the phone).
2. Check the screen on another device – if the backlight is unstable, the problem is the display.
3. Check the board for oxidation or microcracks (especially around the sensor connector).

Cost of repair in the service:

• Replacement of the sensor plume - from 800 to 1500 rubles.
• Repair/replacement of the display module – from 2500 to 4000 rubles.
• Cleaning board from oxidation - from 1000 to 2000 rubles.

5. Application conflict: who is stopping calls?

Sometimes the screen goes out because of third-party apps that interfere with the work of the telephone service.

• 📞 Alternative calls (Truecaller, ExDialer) – may conflict with native firmware.
• 🛡️ Clean Master, 360 Security (antiviruses and optimizers) – block background processes.
• 🔒 Battery-saving apps (Greenify, AccuBattery) aggressively shut down “unnecessary” services.

How to find the culprit:

1. Load your phone in Safe Mode (press the power button → Safe Mode) If the problem has disappeared, it is the fault of third-party software.
2. Remove suspicious apps by testing calls after each deletion.
3. Check the application permissions in Settings → Apps → Permissions (especially phone and sensor access).

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If the problem disappears in safe mode, don’t rush to reset your phone to factory settings. First, remove all apps installed in the last 2-3 weeks – most likely the culprit among them.

Battery and power: an unexpected connection

Few people know, but battery problems can also cause the screen to turn off during calls, because when you talk, the phone consumes more power, and if the battery is faulty, the power controller can force the "uncritical" components, such as the display, to turn off.

Signs that the battery is to blame:

• 🔋 The phone is quickly discharged even in standby mode.
• ⚡ The screen goes out at a charge level below 30-40%.
• 🔌 When connecting charging during the call, the problem disappears.

How to check:

1. Install the AccuBattery app and check the battery health (Health tab).If the value is below 80%, the battery needs to be replaced.
2. Connect the phone to charge and call - if the screen doesn't go out, the battery is the problem.
3. Check Settings → Battery → Battery Use – If the standby consumption exceeds 10% per hour, the battery is faulty.

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If you're using a non-original battery, try temporarily installing your native battery. Cheap counterparts often misinteract with the Redmi Note 8T power controller, leading to malfunctions.

7. When to contact the service: criteria

If you've tried all the methods, but the screen still goes out when you make calls, it's time to carry the phone for repair.

⚠️ Attention: If after falling or getting moisture, the screen not only goes out, but also artifacts, stripes or spontaneous pressing appear - this is a sign of damage to the display module or plume.

• 🔧 The proximity sensor does not respond to test commands (#6484##).
• 💻 Phone firmware “dropped” after a failed update or rooting.
• 🔌 The screen goes out even in safe mode and after resetting settings.
• 🔋 Battery swollen or phone shuts down when the charge level is above 20%.

The cost of diagnostics in official service centers Xiaomi usually is 500-1000 rubles, but sometimes it is free.

Before the service visit:

1. Make a backup of the data (Settings → Additional → Backup).
2. Delete your pattern lock or fingerprint (if the phone is unlocked in the service, the data may be lost).
3. Write down the phone’s IMEI (type *#06#) – this will help to avoid replacement of components.

FAQ: Frequent questions about the problem