Where is the proximity sensor on Xiaomi Redmi Note 7 Pro: circuit, inspection and repair

Xiaomi Redmi Note 7 Pro is one of the most popular smartphones of 2019, but even after a few years of operation, owners face typical problems: the screen does not go out during a call, random pressing when talking or, conversely, the sensor does not respond to the approach of the ear.

In this article, you will find the exact location of the sensor on the front of the Redmi Note 7 Pro, detailed photos of the markup, as well as instructions for diagnosis and repair. We will discuss why the sensor can fail, how to check it without disassembling the phone, and what to do if the problem is not in it, but in the firmware or glass.

If you've never taken a smartphone apart, don't worry: most procedures don't require professional skills, there's enough accuracy and basic tools, and for those of you who don't want to take risks, we'll give you a quick way to get around the problem software.

The Anatomy of the Approximation Sensor: How it Works in the Redmi Note 7 Pro

The proximity sensor in the Xiaomi Redmi Note 7 Pro is an infrared sensor that detects the distance from the screen to an object (such as your ear while you're ringing).

• 🔦 Infrared emitter (IR-LED) — light that is invisible to man.
• 👁️ Photodiode – captures the reflected signal and converts it into an electrical pulse.

When you hold your phone to your ear, the infrared beam bounces off the surface and comes back. The microcontroller analyzes the latency and signal strength, then turns off the screen and touchscreen to prevent accidental taps. The Redmi Note 7 Pro uses the STK3311 sensor (or its analogue), which is integrated into the top camera/sensor module.

It's important to understand that the sensor is paired with a transparent window at the top of the screen, and if that window is contaminated, taped, or damaged, the sensor will malfunction, and it's also affected by firmware: in some custom ROMs or after a failed MIUI update, the sensor can be software-driven.

The exact location of the sensor: diagram and photo

In the Xiaomi Redmi Note 7 Pro, the proximity sensor is located to the left of the front camera, under the top of the screen. If you look at the phone in an upright position, then from left to right at the top are:

1. Approximation/light sensor (combined module).
2. Front camera.
3. Speaker for conversation.

Visually, the sensor looks like a small black hole (~1 mm in diameter) under the glass, which in some instances may be barely visible due to the blackout.

Important: On the Redmi Note 7 Pro, the proximity sensor is combined with the light sensor in one module, which means that when you replace one sensor, you have to change the entire unit.

To accurately identify the sensor, shine a flashlight on the top frame at an angle. The proximity sensor window will slightly shine through in a reddish hue (because of the background). IR-filter, while the light sensor will remain dark.

How to check the proximity sensor without disassembling the phone

Before you disassemble the phone, make sure the sensor is the problem. Here are 3 diagnostic methods that do not require special tools:

1. Test through the engineering menu

The most reliable method is to use the hidden MIUI engineering menu.

1. Open the Phone app.
2. Enter the combination: ##6484## (or #4636## → "Equipment Testing").
3. Select the Proximity Sensor.
4. Close the sensor with your finger – the value should change from 5 (far) to 0 (close).

If the values don't change or if there's an error, the sensor is faulty. If there's a reaction, but the screen doesn't go out during the call, the problem is the firmware or the settings.

2. Verification through the annex

Install Phone Doctor Plus or Sensor Test from Google Play, and in Proximity, you'll see the real state of the sensor, and the advantage of this method is that you can visualize the sensor in real time.

3.A manual test during the call

Call another phone and check:

• 📞 The screen goes out when you approach the ear?
• 🔄 Does the display reopen when removed?
• 🕳️ Is there a delay between approach and reaction?

If the screen is not responsive or is chaotic, move on to the next section.

Frequent Causes of Sensor Failure

In 80% of cases, the proximity sensor on the Redmi Note 7 Pro fails for one of these reasons:

The most common problem is contamination of the transparent window of the sensor, and the dust, the fat, or the glue residue from the protective film, block the infrared signal, and try to gently wipe the top of the screen with a cotton swab dipped in isopropyl alcohol.

If the phone fell or was subjected to a strong vibration (for example, in a pocket while running), the flexible plume connecting the sensor to the motherboard could be damaged, in which case the sensor will work periodically or even turn off, and this can only be diagnosed when disassembled.

⚠️ Warning: Do not use abrasive materials (e.g., eyeglass wipes) or aggressive solvents (acetone, gasoline) to clean the sensor. IR-filter and finally disable the sensor.

Step-by-step instructions for replacing the proximity sensor

If the diagnostics confirmed the sensor malfunction, it can be replaced by yourself.

• 🛠️ Set of screwdrivers (cross, flat, torks) T3-T5).
• 🧲 Screen suction cup.
• 🔥 Hair dryer or thermo-air station (for softening glue).
• 📦 New module of the proximity sensor (original or qualitative analogue).

Important: In the Redmi Note 7 Pro, the proximity sensor is soldered into a flexible plume along with the light sensor and the front camera. So buy the entire module (article: Xiaomi 1903010002 or similar). The cost of the original module is ~ 1500-2000 rubles, Chinese counterparts - from 500 rubles.

Step 1: Disassembling the phone

1. Turn off the phone and remove it. SIM-map.
2. Heat the back cover with a hair dryer (temperature ~60 ° C) and apply it with a plastic spatula.
3. Unscrew 12 screws that hold the metal frame.
4. Carefully disconnect the battery plume, then turn off the display plume.

Step 2: Replace the sensor module

1. Remove the display module (it is attached to the glue, so act carefully).
2. Unpold or disconnect the connector of the old sensor module (located under the top frame of the screen).
3. Install a new module, connect the plume and check the operability.

Step 3: Assembly and calibration

After replacement:

1. Put the phone back together.
2. Turn on the device and check the sensor through the engineering menu (#6484###).
3. If the values are unstable, calibrate at the service center or through MIUI Hidden Settings.

💡

Before disassembling, take a picture of the location of all the plumes and screws - this will help to avoid errors during assembly. Pay special attention to the thin plume of the fingerprint sensor (if you have one in your modification).

⚠️ Attention: When disassembling the Redmi Note 7 Pro, it is easy to damage the plume of the display or battery. If you are not sure about your skills, you should contact the service — ~1000-1500 rubles (excluding spare parts).

Software solutions: if the sensor works, but the screen does not go out

Sometimes the proximity sensor is in good working order, but the screen doesn't turn off during the call.

• 📱 Firmware failure MIUI.
• 🔄 Wrong settings.
• 🛠️ Conflict with installed applications.

Here's what we can do:

1. Resetting sensor settings

Go to Settings → System → Settings Reset → Sensor Resets. After rebooting, check the sensor.

Calibration through the engineering menu

Type ##6484##, select Proximity Sensor and press Calibrate. Follow the instructions on the screen.

3. Disable Smart Blocking

In some versions of MIUI, Smart Locking conflicts with the sensor. Disable it in Settings → Lock Screen → Smart Lock.

4. Install a patch through Magisk (for rooted phones)

If you have Magisk installed, try the Proximity Sensor Fix module from the repository. It fixes errors in the sensor drivers for custom firmware.

💡

Before any firmware manipulations, back up your data via Mi Cloud or TWRP. Wrong actions can lead to a phone blink.

Frequently asked questions