Detailed technical explanation: U disk common fault repair method

Now everyone has a basic USB flash drive. USB flash drive has a great role in our work and life. If there are many important problems stored in the USB flash drive, it will be a problem. What should I do?

1. There is no response when the USB flash drive is plugged into the machine.

Maintenance thoughts: According to the shortcoming scene, the U disk parts have no tasks, and the U disk tools have the conditions. It is the focus of our maintenance. Regardless of the solution, the U disk requires the following conditions:

(1) Power supply, the power required for the main control and the power required by the FLASH, these two are the key, and The U disk circuit is very complicated. If there is no power supply, the fuse is damaged or the 3.3V regulator is damaged. When it comes to the voltage regulator, let's talk about it here. It has three pins to distinguish the power output (5V), ground, Power input (3.3), the task principle is that when the output pin outputs a 5V voltage, the input pin will input a fluctuation of 3.3V. Just find out where there is no source of power, and the situation will be handled very well.

(2) The clock, because the master must be able to do the task at a certain frequency, and the FLASH communication also * the clock signal stops transmitting, so if the clock signal is not available, the master must not be the mission ground. In the reflection of this aspect of the circuit, in fact, the clock generation circuit is very complicated, only need to reflect on the crystal oscillator and its core circuit, because the crystal oscillator is afraid of brushing and the U disk is very complicated to fall on the ground to form a crystal damage, just change the opposite crystal can. Note: The crystal oscillator is unable to measure, and the best central method for judging its good or bad is to replace it with a good crystal.

(3) Master, assuming that the above two conditions are normal, that is, the master chip is damaged. Just change the master.

2, U disk pull out the computer, prompt " unrecognizable device ".

Maintenance thoughts: On this scene, first of all, it is clear that the U disk circuit is basically normal, but there are shortcomings in communication with the computer, and the following points about communication should be reflected:

(1) U disk interface circuit, there is no special component of this circuit is two data lines D+ D-, so when inspecting this circuit, it is only necessary to measure whether the line between the data line and the main control can be normal, usually in Two small resistance ground resistors are connected in series between the data line and the main control circuit to play the role of maintenance. Therefore, it is necessary to reflect whether the resistance values ​​of the two resistors are normal.

(2) The clock circuit, because the U disk and the computer stop communication should stop at a certain frequency, assuming that the task frequency of the U disk and the computer can not be synchronized, then the piecemeal will think that this is an "unrecognizable" Ground equipment " At this time, it is necessary to change the crystal. In practice maintenance, there are many examples of crystal damage!

(3) Master, assuming that the above two points are normal, it can be judged that the master is damaged.

3, you can recognize the U disk, but when you open the prompt " disk has not been formatted " but fragmented and can not be formatted, or prompt " please pull out the disk ", open the U disk outside It is garbled, capacity is not compatible with itself.

Maintenance thoughts: Regarding this scene, it can be judged that the hardware of the U disk itself is not too big, but the software is in use.

Processing: Find the master control plan to repair the tool and you can do it. This requires everyone to see what the U disk master control is to decide.

The shortcomings of the USB flash drive are about the first thing. As for the inability to write files, not to store, etc., it is usually caused by poor FLASH function or bad blocks. Can you have a clear thought after reading? Feel free to clarify that U disk is different from MP3, she does not have the firmware, but some manufacturers put their own software outside, low-level will have no land.

If you have a problem with the USB flash drive, you can use the above method to repair it yourself. If it is a small problem, you can basically succeed. If your USB flash drive is really poisoned, consider eliminating it.