The reason my USB drive was plugged into the computer didn't respond.

Sometimes we will encounter a U disk plugged into the computer without any response to the problem, the reason, the U disk want to work must have the following conditions, a comparison of the basic can find your U disk may belong to the following reasons:

(1) power supply, divided into the main control of the required power supply and flash required power, these two are the key, and the U disk circuit is very simple, such as no power supply is generally the insurance inductance damage or damage to the 3.3V voltage regulator block, said the voltage regulator here also said, its three pins are power input (5V), ground, power output ( 3.3, the working principle is that when the input foot input a 5V voltage, the output foot 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.