Tutorial on Redmi 9A: No Power
In this tutorial, I will show you how to troubleshoot and fix a Redmi 9A smartphone that won’t turn on. This is a common problem that can be caused by various factors, such as a faulty battery, a damaged power IC, a short circuit, or a software glitch. I will guide you through the steps of diagnosing and repairing the device, using some tools and techniques that I learned from my training.
Redmi 9A Tools and Materials
To perform this tutorial, you will need the following tools and materials:
- A multimeter
- A power supply
- A soldering iron
- A heat gun
- A tweezer
- A screwdriver
- A prying tool
- A new power IC (MT6357CRV)
- A new capacitor (C504)
Step 1: Check the Battery Voltage
The first thing to do is check the battery voltage of the Redmi 9A. To do this, you need to open the back cover of the phone and disconnect the battery connector. Then, use the multimeter to measure the voltage across the battery terminals. The normal voltage should be around 3.8 volts. If the voltage is too low or too high, it means the battery is defective and needs to be replaced.
Step 2: Check the Power Key
The next thing to do is to check the power key of the Redmi 9A. To do this, you need to connect the battery connector again and press the power key. Then, use the multimeter to measure the voltage at the power key line, which is located at the edge of the motherboard. The normal voltage should be around 1 volt. If the voltage is not present, it means the power key is faulty and needs to be replaced.
Step 3: Check the Power IC
The power IC is the main component that regulates the power supply of the Redmi 9A. It is located under a metal shield on the motherboard. To check the power IC, you need to remove the metal shield and heat the power IC with a heat gun. Then, use a tweezer to gently shake the power IC and see if it moves. If the power IC moves, it means it is loose or damaged and needs to be replaced.
Step 4: Check the Capacitor
The capacitor is a small component that stores and releases electric charge. It is located under the power IC on the motherboard. To check the capacitor, you need to use the multimeter to measure the resistance across the capacitor terminals. The normal resistance should be infinite. If the resistance is low or zero, it means the capacitor is shorted and needs to be replaced.
Step 5: Replace the Power IC and the Capacitor
To replace the power IC and the capacitor, you need to use the soldering iron and the heat gun to desolder the old components and solder the new ones. Make sure to align the pins of the power IC correctly and apply some flux to the solder joints. Then, use the multimeter to check the voltage and resistance of the new components and make sure they are normal.
Step 6: Reassemble the Phone and Test
The last step is to reassemble the phone and test if it works. To do this, you need to reconnect the battery connector and the metal shield and put the back cover back on. Then, press the power key and see if the phone turns on. If the phone turns on, it means you have successfully fixed the problem. If the phone still doesn’t turn on, it means there is another problem that needs further investigation. our visit here
In this tutorial, I have shown you how to troubleshoot and fix a Redmi 9A smartphone that won’t turn on. I have explained the possible causes of the problem and the steps to diagnose and repair the device. I hope you have learned something useful from this tutorial and can apply it to your situation. If you have any questions or feedback, please leave a comment below. Thank you for reading, and happy repairing!