Why Xiaomi Redmi 9 has problems: a full analysis of the causes and solutions

Introduction: Common Xiaomi Redmi 9 Problems and Their Roots

The Xiaomi Redmi 9, launched in 2020, has become one of the most popular budget smartphones due to its price-performance balance. However, even such proven models have typical malfunctions over time, from software glitches to hardware breakdowns. Owners often face questions: why the phone does not turn on after charging, why the battery goes down quickly or why the sensor does not work after a fall.

In this article, we have systematized 12 main reasons why Redmi 9 may behave incorrectly, and offered proven diagnostic and solution methods. It is important to understand that some problems are solved independently (for example, resetting settings or cleaning the cache), and others require the intervention of a service center – especially if it is a motherboard damage or a bloated battery.

We also took into account the specifics of the model: Redmi 9 is equipped with a processor MediaTek Helio G80, It's prone to overheating under high loads, and it's a 5020 mAh battery that loses 30 percent of its capacity after 2-3 years of operation.

1.The phone does not turn on: from simple to complex

If your Xiaomi Redmi 9 doesn’t respond to the power button, the causes can range from a dead battery to a critical firmware failure.

• 🔋 Connect the original charging cable to the outlet (not to the USB-The port of the computer) and wait 15-20 minutes. the charging indicator should light up.
• 🔌 Try another charger with Quick Charge 3.0 support (from 18W).
• 🔄 Hold the power button for 10-15 seconds for forced reboot.
• 📱 If the screen flashes or vibrates but does not turn on, this is a sign of bootloop failure).

If the phone still doesn’t show signs of life after charging, check:

• 🔧 Charging connector: often it clogs with dust or deforms. Light with a flashlight - contacts should be clean and smooth.
• 🔋 Battery: If the phone fell or got wet, the battery might swell. Signs of bloating: screen "lifted" at the edges, body deformed.
• 🖥️ Firmware: If you upgraded the software before you shut down, it may have crashed.

⚠️ Warning: If the phone heats up when you connect to a charger, but it doesn't turn on, it could be a short circuit on the board!

Fast battery discharge: is the battery to blame?

Redmi 9 is famous for its 5020 mAh battery, but after 2-3 years, many users notice that the charge lasts only a few hours.

1. Software: background processes, viruses, unoptimized applications.
2. Hardware: battery wear, damage to the power controller.
3. Custom: frequent full discharges, the use of non-original charges.

For diagnosis:

1. Go to Settings. → Battery → Battery usage and check which applications use the most power. Normal standby consumption is 0.5-1% per hour.
2. Install the AccuBattery app (available on Google Play) to analyze the battery status. If the capacity has dropped below 3,500-4000 mAh, the battery needs to be replaced.
3. Check the temperature of the phone in Settings → The phone. → Status. Normal: 30-40.°C on charging, up to 45°C under load.

💡

If the phone is discharged overnight by 20-30%, turn on the mode Saving charge in the battery settings and turn off background activity for social networks (Facebook, Instagram).

3.Overheating: When it's normal and when it's cause for concern

MediaTek Helio G80 Redmi 9 is prone to heat up under intense loads (games, video editing, long-term video shooting), however, if the phone is warming up in standby mode or with simple tasks (calls, instant messengers), this is an alarm signal.

The main causes of overheating:

• 🔥 Charging connector contamination: dust and debris interfere with normal contact, leading to heating.
• 🖥️ Firmware failure: after update MIUI Some processes may be looped.
• 📱 Damage to the thermopaste: over time it dries out and the heat sink deteriorates.
• ☀️ Direct sunlight: Even 10 minutes in the sun can heat the body up to 50°C.

How to lower the temperature:

1. Close all background applications through Recent → Close everything.
2. Turn off your mobile data or Wi-Fi if you are not using the internet.
3. Remove the case (especially silicone) - it worsens heat transfer.
4. If the phone is heated to 50°C+, Turn it off for 30 minutes.

⚠️ Warning: If Redmi 9 heats up to 60°C and above, this can lead to battery detachment or damage to the screen!

Make a backup copy of the data|Check for viruses|Clear the cache in the storage settings|Reset the settings to factory|Contact the service-->

4.Sensor problems: the screen does not respond or does not work correctly

Sensor faults on Redmi 9 are divided into two types:

1. Software: calibration failure, application conflict.
2. Hardware: damage to the plume, cracks on the display, ingress of moisture.

First, try the software methods:

• 🔄 Restart your phone – sometimes the sensor “hangs” due to a temporary glitch.
• 📱 Remove the latest installed apps (especially launchers or games).
• 🔧 Reset the sensor settings: go to Settings → System system → Additionally. → Resetting settings → Resetting sensor settings.
• 🛠️ If part of the screen is not responding, check for microcracks (they may be invisible to the naked eye).

Hardware breakdowns require repair:

• 💧 If the phone fell into the water, even a brief ingress of moisture could oxidize the contacts of the sensor.
• 📉 If the screen is "floating" (scrolling independently), this is a sign of detachment of the plume.
• 🔨 If the sensor only responds to a strong press, the digitizer (top layer of the screen) may have been damaged).

5. Communication problems: no network, no Wi-Fi or Bluetooth catches

If Redmi 9 has stopped catching the network, does not connect to Wi-Fi or constantly loses connection to Bluetooth devices, the reasons can be in both settings and hardware.

Diagnostics of problems with mobile network:

• 📶 Check if the mode is on. 4G In Settings → SIM-maps and mobile networks → Preferred type of network.
• 🔄 Reboot the phone and remove/paste SIM-map.
• 📡 If the signal is lost in certain places, the operator may have the problem.
• 🔧 Reset network settings: Settings → System system → Additionally. → Resetting settings → Resetting network settings.

Wi-Fi problems:

• 🌐 Make sure the router is running in the 2.4GHz band (Redmi 9 does not support 5GHz in some regions).
• 🔒 If Wi-Fi is connected but the internet is not working, check your settings. IP (shoulder DHCP).
• 📱 Update the router’s firmware – outdated versions may conflict with MIUI.

Bluetooth does not find the devices:

• 🔊 Make sure the device (earphones, column) is in pairing mode.
• 🔄 Turn off/turn on Bluetooth in the notification curtain.
• 📱 Reset Bluetooth Settings: Settings → Connected devices → Bluetooth settings → Reset.

💡

If the phone doesn't catch the network after a fall, the motherboard's communication module is likely damaged, in which case the soldering service needs repair.

6 Camera not working: black screen, blur, errors

Cameras on Redmi 9 (main 13 MP) + 8 MP wide angles can malfunction due to software errors or physical damage:

• 📷 Black screen when opening the camera.
• 🔍 Blurred pictures even in good lighting.
• ⚠️ Error: "I failed to connect to the camera".
• 📹 Video recorded with artifacts (strips, jerks).

Decisions:

1. Restart your phone – sometimes the camera freezes due to memory shortage.
2. Clear the Camera app cache and data in Settings → Annexes → Camera. → Warehouse.
3. Check if the lens is covering anything (dust, protective film, cover).
4. Update the firmware - in new versions MIUI Often fix camera bugs.
5. If the camera is turning on the focus, it is a sign of damage to the mechanism (repair is needed).

⚠️ Warning: If the camera stopped focusing after the fall, don’t try to knock on the phone or blow into the lens – this will aggravate the problem!

7.The sound is lost: speaker, microphone or headphones

The sound problems on Redmi 9 fall into three categories:

1. Software: driver failure, incorrect settings.
2. Hardware: damage to the speaker, oxidation of contacts.
3. Mechanical: clogging of the speaker grid, getting moisture.

Diagnosis:

• 🔈 If the sound is lost only in headphones, check the 3.5 mm connector for debris.
• 🎤 If the person can’t hear you, wipe the microphone (located at the bottom of the phone).
• 🔊 If the sound is distorted (wheezing, crackling), it can be damage to the speaker membrane.
• 📱 Check the sound settings: Settings → Sound. → Sound quality (should stand high).

Decisions:

• Restart your phone – sometimes the sound disappears after the update.
• Turn off Bluetooth devices – they may conflict with the speaker.
• If the sound is only at maximum volume, it is a sign of wear and tear of the speaker.
• To clean the headphone jack, use a toothpick with cotton wool soaked in alcohol.

8.The phone brakes: how to return the speed

Redmi 9 with 4 GB of RAM and Helio processor G80 It's not a flagship, but even it has to handle everyday tasks. If the phone starts to lie, the reasons may be:

• 🗑️ Completed storage: when filling the memory at 90%+ brake.
• 📱 Too many background processes: MIUI tend to keep applications in memory.
• 🔄 Outdated firmware: new versions MIUI optimized better.
• 🦠 Viruses or Advertising Software: Can load the processor with hidden tasks.

How to speed up work:

1. Clear the cache: Settings → Storage → Clear the cache.
2. Turn off animation: Settings → The phone. → Version. MIUI (Press 7 times, then Developer Settings → Scale of animation → Choose No Animation).
3. Remove unused apps and transfer the photo/video to the memory card.
4. Enable Easy Mode in Settings → Special facilities.

💡

If the phone brakes even after resetting, it could be a sign of wear and tear on the flash memory (especially if the storage is like eMMC), in which case only a replacement chip will help.

FAQ: Frequent questions about Xiaomi Redmi 9