USB flash memory device failures detailed maintenance methods

The following failure in the maintenance, we should exclude damage and PCB board USB interface, Weld, and USB extension cable under normal circumstances, and then repair to judge.
1, USB flash drive plugged into the machine did not respond
Maintenance ideas: According to the breakdown phenomenon judge, USB flash memory device machine did not work, USB flash memory device tools have the conditions to maintain our focus. Regardless of any USB flash device you want to program tools must have the following conditions:
(1) power supply, into the master power supply and the necessary power needed to FLASH, the two is the key, and USB flash memory device circuit is very simple, if there is no power inductors are generally damaged or 3.3 Insurance V regulator block damage, said regulator block and then click here, also said its three pins are the power input (5V), ground, power output (3.3), the working principle is that when the input pin of a 5V input voltage, output pin will output a stable 3.3V. Found where there is no power as long as the root of the problem will be solved very well.
(2) clock, as master at a certain frequency in order to work with FLASH communication also depends on the clock signal for transmission, so if there is no clock signal, the master will not work. Check this circuit in a time when, in fact, the clock generating circuit is very simple, only need to check the crystal and its peripheral circuits can, for fear of brushing and crystal USB flash memory device is very small and easy to fall to the ground caused by crystal damage, as long as the replacement the same crystal can be. Note: The crystal can not be measured, the best way to judge good or bad is a good substitution to determine the crystal.
(3) the master, if the above two conditions are normal and that is the main chip damaged. As long as the replacement of the master. .
2, USB flash memory device into the computer, it says "does not recognize the device."
Maintenance ideas: for this phenomenon, the first USB flash device illustrates the circuit normal, but only communications with the computer malfunction, and for communications to check the following points:
(1) USB flash memory device interface circuit that no special device is two data lines D + D-, so check this circuit as long as the measurement data lines to the master can be between the lines is normal, usually in the data line and the main control circuit will be connected in series between the two small resistor values to play a role in protection, so check both the resistance is normal.
(2) clock circuit for USB flash memory device to communicate with the computer to be carried out at a certain frequency, if the USB flash memory device operating frequencies and the computer does not sync, then the system will think it is a "device not recognized" the. At this time we should change the crystal. The actual maintenance of crystal damage is really a lot of examples!
(3) the master, if the above two checks are normal, it can determine the master damaged.
3, USB flash memory device does not accidentally fall into the water
Maintenance ideas: Because Flash is not charged, it will not soak in water a short circuit, if the general does not affect the correct use of dehydration. It was forced on the use of hair dryer fell into the water drying approach in dealing with flash, but it must not be taken as:
(1) dry although dehydration can reduce the time, but the damp of the circuit board-based rapid drying due to external heating, but not synchronize the internal moisture evaporation, this time due to internal stress and even lead to rupture of the circuit board is damaged, it simply is not heating and drying take.
(2) The former is not as pretreatment. Although flash memory after soaking in water will not short circuit, but when we will it, after drying, or dry, although the evaporation of water, but water, salt and other impurities are attached to the circuit board, these things are often good conductor of electricity , when electricity use will inevitably lead to memory corruption. So do not make direct dry pretreatment also unworthy.
Do not rush flash memory fell into the water after drying, use a clean water rinse to ensure that there is no water retention flash drives, the best conditions to wash with ethanol. This done the sooner the better. If not treated soon and flash memory has naturally dried, and suggested it apart, remove the circuit board with anhydrous alcohol and soft brush to clean the base plate, and then flash and air dry.
4, can recognize USB flash memory device, but when prompted to open the "Disk not formatted" but the system is unable to format, or prompt "Please insert the disk", open the USB flash memory devices which are garbled, and so does not match capacity with itself.
Maintenance ideas: for this phenomenon, USB flash memory device can determine the hardware itself is not much problem, but software problems
Solution: find the master plan of repair tools and do some on it. This should all look at their own USB flash drive the master is to determine what programs
USB flash memory device failure probably is that these major problems. But who can not write files, do not store such phenomena are generally FLASH or poor performance caused by bad blocks. After reading all there is no clear idea of it. Casually explain, USB flash memory device is different from the MP3, he is said there is no firmware, but some manufacturers put their own software inside, it will not look at the low cell.