It may not match the type of interface (1.1.1,2.0), you can try the case mouth "Unrecognized USB Device" approach 1.Front USB wrong.When the front USB port on the USB line corresponding to the motherboard and to the positive and negative phase counter-chassis of such failure occurs, it is quite dangerous because the positive and negative reversal is likely to be destroyed so that the USB device. So far as possible the enclosure of the USB interface with a less extension line.Fracture may also be a problem, another USB port facie. 2.Lack of USB interface voltage.When the mobile hard disk connected to the front USB port is likely to occur not recognize the fault of the equipment.The reason is that mobile hard disk power is relatively large voltage requirements are relatively strict, pre-interface may not provide enough voltage, of course, poor power supply may also cause this problem.The solution is not a mobile hard disk connected to the front USB port, replace the power inferior low power or use an external power supply of the disk cartridge, if able to do so. 3.System motherboard and compatibility issues.Oh such failures in the most famous is the NF2 motherboard and USB compatibility issues.If you encounter this problem is in the NF2 motherboard, then you can install the latest nForce2 dedicated USB2.0 drivers and patches, the latest motherboard patches and operating system patches, or does not work, then try to refresh the motherboard BIOS can usually be resolved. 4.Or system BIOS issues.When you disable the USB in the BIOS or operating system will occur USB device is not recognized in the system.The solution is to open the options associated with the USB device.It is to start by F2 or DEL key to enter the BIOS, to enable usb device select enable. 5.Plug to be careful, do not pull out when reading and writing, or may be burned chip.XP, the taskbar icon extra USB devices, open the U disk icon will appear in the list, select the device to disable, and then you unplug the device, that would be more secure. In fact, the software determines hardware problems is very simple, in another machine or another system (98 to drive oh) try it.Some minor problems may wish to use specialized software to format under.WINDOWS also remind you to select the next FAT format, not FAT32 election. U Alert does not recognize the USB device repair the fault tips Figure: This failure was largely caused by U disk interface circuit part of. 1, a first transducer USB extension cable or another USB port, excluded U-off factors other than. 2, shake plug U disk to see if there is loose. 3, open U disk enclosure, the four foot USB interface welding again. 4, the fault persists.We know that the resistance of the data line has two protective effect (see below) between the master to, a measurement with a multimeter where open. 5, is removed from a 27 ohm resistor bad MPU put, troubleshooting. Summary: U disk failure is generally easier to repair, emergency situations can also be shorted directly to this resistance. Maintenance Example Two: a Reidio card 128M U disk prompt does not recognize the device is plugged into a computer USB hole.This U disk is ChipsBank program. Remark: FIG makeshift diode as the wire bonding, the maintenance should be broken off tripod IC, diodes soldered directly to the circuit board. There are parts of the same size should put the regulator IC. Maintenance process: 1, based on failure analysis, can eliminate the problem is software. 2, U-apart first look oscillator, presence or absence of a flash memory Weld 3, with the substitution of spare 12M crystal, the fault persists 4, V USB interface multimeter test voltage is + 5V 5 normal, and then measuring the regulator IC 5V input terminal is normal, the measured output of the regulator IC of only 1.3V, normal should be 3.About 3V 6, since no heat is like the chip, is determined damaged regulator IC. 7, not just the hand that regulator IC, a diode and an emergency tripod between IC input and output, as shown in. 8, Troubleshooting. Unrecognized USB device: Unknown USB Device. Many people have encountered a problem, the so-called ''unrecognized'' for the operating system, or the extent of a problem with the drive, or USB device problems, or a computer with a USB device connection fails, to solve the problem from this method also started several. For different devices have different approaches to understand the conditions of USB devices need to work as well as some factors that may affect the USB device is working properly, it will help solve the problem. The following are some of the conditions to ensure that the USB device can operate normally: (1) USB device does not have any problems - can be tested on other computers, guaranteed to work; (2) USB Interface without any problems - can be connected other USB devices on this interface testing; driver (3) USB device has been installed correctly, if there is a detailed description of the USB device, be sure to carefully review appropriate documentation, follow the instructions to install the appropriate drivers; Windows 2000 after the operating system to recognize most USB devices, Windows 98 operating system can be installed before the USB device driver carrying or installing generic USB device driver. The following are some situations may affect the normal operation of USB devices: (1) USB device has malfunctioned (formerly the same conditions can be used normally, and now there is a problem); (2) USB interface has problems, such as a.USB front interface reverse polarity, which may cause the USB device to burn, so be sure to carefully look at the motherboard manual, correct connection; b.Interface brownouts, some mobile hard drives often have this problem, the back of the host USB port tend to be more reliable than the front USB port number; c.Board with the operating system compatibility problems, to install the latest motherboard drivers such problems can be avoided to the maximum extent; D.Bios prohibiting the USB device, possibly by changing the corresponding settings in the BIOS to resolve; e.Operating system problem can be solved by reloading the operating system; (3) USB driver has a problem: If you suspect a problem with the drive, it should ensure you have the latest drivers for the corresponding model of the device or confirm the operating system without installing special driver, find the latest drivers can go online via the device manufacturer''s home page. When a USB device problems, in addition to the actual error message to find a solution outside, but also carefully check the USB device specific brand, model, producer, at the time of the search results include information, you can more easily find their solutions method. Some devices such as the USB plug in a connected state requires frequent laborious temporary malfunction, operating systems keep a "USB device does not recognize" this annoying tips can be temporarily shut down in the Universal Serial Bus Controller Device Manager in the corresponding USB port or disable the corresponding USB device. About reason unrecognized usb device is not online MP3 There are several possible, I come into contact with a variety of MP3, roughly summarize Solution: 1.After insertion of MP3 computer settings, the computer will pop up in the lower right corner of some information to connect this USB device is trying, sometimes will pop up dialog box allows the user to select, some users will not see the point of no, or because some initial computer setting the problem, prohibit some of the features of USB. Solution: Right-click "My Computer", choose "Properties" - "Hardware" - "driver signature", where "Ignore" and click "OK".Then plug MP3, or even if not, then right-click "My Computer" - "Properties" - "Hardware" - "Device Manager", find the "Universal Serial Bus controllers", right, then "scan for hardware changes.". 2.MP3 CD-ROM driver problems often with "98 Driver", "upgrade tool" in the system than in 2000, although in theory need to install MP3 can also be linked, but often drive installed, make online becomes more smooth.So try to install these tools, if there is no "98 driven", they "upgrade tool" to install it (some MP3 drive integrated in the upgrade tool). 3.MP3 voltage problem in itself because now the trend is to reduce the cost of doing everything possible to MP3, so companies continue to adopt new programs, new master, a new FLASH chip, not to say that these new things to cut corners, the problem is that these new things often require long-term debugging in order to achieve the best, but the market situation can only allow MP3 factory testing on the production line on a computer interface, so often appear not online, off the disk and so on. In this case the user needs to try several times, for different plug USB interface, adding a good quality single USB cable (typically the thicker the better, better than the iron and copper), MP3 and ensure normal power supply (charging is the full power again). 4.After long periods of use, it does not appear after some online MP3 unused for long periods, not online, not even charge.MP3 is not mainly due to the power off, do not lead to long-term excessive discharge, due to reach the starting voltage. Solution is, after the MP3 is connected to a computer or a charger, repeated pulling / into the USB port and opening / closing the power switch (ON / OFF key, if not repeatedly press the PLAY button).For example, the plug in a USB interface, OFF ON / OFF charging for 2 minutes apart ON / OFF charging for 2 minutes, and then re-insert pull down, and then charge 2 minutes.The aim is to get into the MP3 to a small number of electric charge, to starting voltage. 5.If these remedies do not solve the problem, the basic problem itself can certainly MP3.At this point, it should be timely repair or returned, so as not to miss the warranty period.Strongly opposed to user-disassemble, more than all types of MP3 phones, and often require the original program to re-upgrade, so disassemble most of the lead can not enjoy the free service.We do not recommend users to upgrade themselves to MP3. System error "Unrecognized USB Device" failure phenomenon using the computer loses power unexpectedly when U disk, U disk after reboot does not work properly, plug the system error "Unrecognized USB Device".The original use of other USB devices can be used normally, will prompt the same error message.Other USB devices plugged into the USB port of a computer, can work. [Analysis] fault phenomenon from the point of view, USB devices and motherboard interfaces are not damaged, suspected to be accidental power failure, the system is set incorrectly. [Problem] from the window "Control Panel" into the adding and removing hardware will all USB devices are deleted, re-install the USB device driver needs to use.Restart the computer, U disk and other USB devices plugged into the original failed interface to work properly. Unrecognized USB device - mobile hard disk notebook hard drive failure, inserted in the front USB port can not be recognized. This case, a large reason is the supply problem. Since USB hard at work also need to consume a certain amount of energy, if directly through the USB interface to take power, is likely to be insufficient supply.Thus, almost all of the mobile hard disk come with a separate external power transfer interface through a keyboard or the PS2 to take power, long time in advance, or by an external power supply connected PS2 keyboard connected to the adapter cable, ensure that a mobile hard disk provides sufficient try again after power, then it should be properly used.Need to remind everyone that, to ensure that all previously recommended the use of mobile hard disk has enough power, or is likely to result in hard disk damage due to insufficient power supply. For never used USB external device of friends, but also even if the drivers are installed properly possibilities the system can not detect USB hard drives appear, mainly due to the motherboard default CMOS port is closed, if it is not set to open state, then naturally we can not detect Windows mobile hard drive.To solve this problem, we can re-boot into the CMOS settings window, and in the "PNP / PCI CONFIGURATION" column in the "Assign IRQ For USB" one set to "Enable", so that the system can be used to assign a USB port the interrupt address. There may be a USB interface type does not match the result in the mobile hard disk unusable.For example, configuration of your computer USB port is 1.1 standard, and the purchase of mobile hard disk is USB 2.0 standard interface, which requires a computer and a mobile hard disk connected to the cable must support USB 2.0 Standard.Because the high-speed mobile device into a low-speed hub, the device may not be installed properly, and some friends while using USB mobile hard disk also be used, in order to facilitate the direct use of the supplied USB USB 1.A standard cable, thus leading USB 2.0 standard mobile hard drive is not recognized correctly.As long as the cable replaced USB 2.0 standard can solve this failure.
Download the driver wizard to install u disk drive
1, into the bios, setting default values of, load optimal default.
2, reinstall the system.
3, if not enough, or the controller may supply the motherboard usb problem, try another power.