Tips for quickly identifying whether a U disk Master is damaged

1, U disk inserted into the machine without any reaction

Maintenance ideas: According to the fault of the judge, U consolidation machine does not work, and U disk tools to be equipped with the necessary conditions is the focus of our maintenance. Regardless of any scheme of the U disk want to work must have the following conditions:

(1) power supply, divided into the main control of the required power supply and flash required power supply, these two are the key, and U disk circuit is very simple, such as no power supply is generally the insurance inductance damage or 3. 3V Voltage regulator block damage, when it comes to the voltage regulator block again here, its three pins are power input (5V), ground, power output (3.3), the principle is that when the input foot input a 5V voltage, output feet will output a stable 3.3V. As long as we find out where there is no source of power, the problem will be solved well.

(2) The clock, because the main control to work at a certain frequency, with flash communication also * clock signal transmission, so if the clock signal does not, the main control will not work. And in the examination of this circuit, in fact, the clock generation circuit is very simple, only need to check the crystal oscillator and its peripheral circuit can be, because the crystal is afraid of brush and U disk compact very easy to fall on the ground caused by crystal damage, as long as the replacement of the same crystal vibration can be. Note: Crystal oscillator is not measurable, the best way to judge its quality is to replace a good crystal vibration to judge.

(3) Master, if the above two conditions are normal that is the main control chip damage. Just change the main control.

　　2, U disk inserted into the computer, prompted "unrecognized equipment"

Maintenance ideas: For this phenomenon, the first point that the U disk circuit is basically normal, but only with the computer communication problems, and the communication has the following points to check:

(1) U disk Interface circuit, this circuit does not have any special components is two data line d+ D, so when checking this circuit as long as the data line to the main control between the line is normal, generally in the data line and the main control circuit will be strung between two small resistance resistors, to play a protective role, So check the resistance of these two resistors is normal.

(2) clock circuit, because U disk and computer communication to be in a certain frequency, if the U disk work frequency and computer can not sync, then the system will consider this is an "unrecognized device." At this point will change the crystal vibration. and the actual repair there are many examples of crystal vibration damage!

(3) Master control, if the above two-point inspection is normal, then you can judge the main control damage.

　　3, you can recognize U disk, but open the prompt "disk has not been formatted" but the system can not be formatted, or prompted "Please insert Disk", open U drive inside are garbled, capacity and itself does not match.

Maintenance ideas: For this phenomenon, you can judge the U disk itself hardware is not too big problem, but the software problem.

Workaround: Find the Repair tool for the master scheme and get it done. This will everyone to see the main control of the U disk is what the plan to decide.