Huawei nova9 A9 turns on the bright logo and automatically restarts, and maintenance is found.mobile phoneThe resistance on the back of the battery is OL, which means that the wire is broken. We flew the wire directly, and after testing, we found that the mobile phone was turned on normally. How exactly is it repaired? Please see below:
Disassemble the machine first for testing, and the measuring switch tube 5V is also normal, considering that mobile phone I have fallen, so let's try to short-circuit the switch tube first. If the fault remains after short-circuiting the switch tube, then give priority to whether there is virtual welding of the charging inductor. The specific maintenance process is as follows:
IPad7 A2197 customer said that it would not be turned on when it was used, and directly removed the ammeter on the motherboard to see the current, and found that the standby current was normal. After triggering, the current was only 22mA. After looking at the CPU model, it was found that it was the commonly used A10 CPU. This CPU caused quite a lot of iPad with small current, which was a common problem, so the CPU was directly redone.
A Huawei Nova 7se that had been heavily dropped failed to charge, which was caused by inductance virtual welding after detection. See how the professional repairman repairs the maintenance steps below!
First, measure whether the 5V voltage of the tail plug is normal, and consider whether the charging IC and U2 on the motherboard are burnt out together. Because it is a double-layer motherboard, we will separate the motherboard first, and then measure it in layers to see if there is any abnormality in the resistance voltage of the charging IC and U2.
Huawei Mate 40 Pro, say yesmobile phoneI can't hear the sound on the phone recently, which affects communication with others when answering the phone, but it is normal to play music. So, what is the problem with this Huawei Mate 40 Pro? Look at how the professional master operates below!
The measured voltage is not generated. The first step of starting is to convert the battery voltage into the main power supply. The measured resistance of the main power supply is normal and there is no short circuit. Then we directly disassemble a charging IC of the same model and install it. The specific maintenance process is as follows:
Huawei Mate 30 Pro 4G version,mobile phone The fault is that the mobile phone does not display, you can hear the sound when you make a phone call and charge, but you can't see the screen display. In view of this problem, how should we deal with maintenance? The following professional maintenance master tells you!
The actual fault is that the phone can't be called because there is no base band, because Apple is above X.mobile phone They are all designed with a double-layer motherboard, and the base band is in the lower layer, so we can directly disassemble the machine for layering, which is caused by virtual welding of the upper and lower layers. After planting tin on the lower layer and attaching it to the upper and lower layers again, it is confirmed that there is no short circuit, and the installed button screen is booted into the system and found that the base band already exists, and the serial number is normal.
