Why did the USB ports stop working?

Many computer owners still remember the times when all peripheral devices connected to the system blocks through serial (COM) and parallel (LPT) ports. The standards were fairly simple to implement, which had the most positive effect on the cost of motherboards and external equipment using these interfaces. Their shortcomings were the inability to connect peripheral devices "on the go", without turning off the power of the system, as well as low throughput. However, this was a kind of payment for "cheap", and before the era of multimedia no one paid attention to these features . With the beginning of the active dissemination of multimedia technologies (digitization and voice transmission, images), it was necessary to think about replacing COM and LPT. The result of the work of several large companies was the appearance in 1996 of the first version of the USB interface (universal serial bus), which allowed for speed scaling and supported the hot Plug & Play connection. Since then, several generations of the standard have changed, and at the moment, version 3.0 is actively promoted. Unfortunately, despite all the efforts of developers and universality, until now many owners of computer systems sometimes notice that USB-ports have stopped working. And for no apparent reason. Interestingly: the USB port device is very simple: there are only 4 wires in the plug (sometimes 5, the fifth - the screen), two of which transmit data, and the remaining two serve for power.

Repair or service

Everyone knows that to ensure the uninterrupted operation of electrical appliances, it is necessary to periodically perform an audit. Washing machine should be cleaned, from the ventilation grilles of the TV you need to sweep the dust, and the mobile phone - to charge and clean from unnecessary programs. But the computer, as a rule, is a "thing in itself": after installation of the system unit, it is often touched by the feet under the table, the radiators are not cleaned, and that few people have ever heard of adding oil to the fan bearings. Is it any wonder that there comes a time when USB ports are suddenly disconnected? Fortunately, in 90% of cases it is possible to restore working capacity independently, without going to the service center and unplanned costs.

Basic input and output system

In case of any malfunction of the serial bus, it is necessary to check the settings in the motherboard configuration program. It is present in both portable and stationary computers: it performs key block testing and initial setting of operating modes, including the ability to lock USB. This program is called BIOS (basic input / output system). In modern systems, it was replaced by UEFI, but the basic principle of functioning has been preserved. Obviously, every computer owner simply has to know how to include USB ports in the BIOS of the motherboard. Otherwise, a minor malfunction or someone's joke - and will have to go to the service center, although everything can be solved on its own in a minute.

Configuring the board

To get into the BIOS, it is necessary to press the Delete button many times after turning on the system unit . On laptops, this function can be assigned to F2, which is reported on the screen with a logo (by clicking a pause, you can read the inscription).

Unfortunately, when we talk about how to include USB ports in the BIOS, we can not describe the exact algorithm of actions, because, depending on the configuration program implementation, the placement of the items will be different. The user must "walk" through all branches of the menu, looking for control of the USB-controller, or take the instruction book to the board and with its help to find a link to this item. So, if the USB ports have stopped working, then on some boards you need to open the Advanced BIOS Features and find the USB settings. By pressing Enter, you can select Enabled / Disabled or On / Off. Use should be allowed. On other motherboards, go to the Integrated Peripherals item and find the OnChip USB Controller. The status is Enabled. It's also useful to check that Legacy USB Support is also involved. So, let's sum up the BIOS: the user's task is to activate the Universal Serial Bus controller.

Operating System Registry

Windows allows at the program level to prohibit the use of ports by changing only one digit in the settings. However, this only works for devices that have already been connected to this computer, and for them, drivers for USB ports have been installed. To disable / enable the bus, you should:

- press the combination Win (button with the symbol "windows") + R;

- In the appeared line type regedit (execute);

- follow the branches to HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ USBSTOR;

- find the line Start and double click the mouse to change the value from 4 to 3. This is the normal mode of operation. Changing the same trio to the four, on the contrary, prohibit the use of USB.

Changes will become visible after the reboot. We do not recommend without having to "play" with this item, as there may be problems with the mouse and keyboard connected to the corresponding connectors.

Connecting USB ports on personal computers

For ease of use with the system unit, some of the connectors are located on the front panel of the case. In particular, these are the jacks for the speakers / microphone and USB. Indeed, it is very convenient when connecting the appropriate periphery not to look for an unused connector from the back of the system unit, but to use easily accessible sockets. At the same time, such an implementation has a disadvantage that the USB ports of the front panel are connected by means of a cable that is stretched inside the case to the motherboard of the contacts on the motherboard. Hence the problem. The USB cable should not be made from penny wires, rather than cheap Chinese-made cases, but fully meet the requirements for resistance, soldering / crimping, length, etc. The connectors on the reverse side are directly soldered to the board and, consequently, more reliable .

So, if the USB ports on the front panel of the system do not work, the USB ports should stop working, then you need to remove the case cover, find a USB comb on the board with the connected loop (signed), carefully disconnect the pins and the plug and reconnect. Sometimes it's quite effective to simply reconnect to a neighboring comb. For example, if the cable goes to USB 5-6, then it must be attached to 7-8.

By the way, the problem with the front panel connectors is one of the most common. In case there is no time to open the case, the periphery can be connected to the sockets on the rear wall.

"Eat is served", or Problem with food

Although the specifications for the universal serial bus indicate that the maximum current per port is 500 mA for the second version and 900 mA for the third version, this does not mean that all devices can be connected to the same devices at the same time, and everything will work. Moreover, this is the shortest path to the problems and the question "why USB ports have stopped working." All modern boards have a built-in universal bus controller, which, in simple language, controls all the corresponding connectors. Physically, it is an electronic device that has the ability to directly access memory with a designated interrupt and is able to partially free the central processor from routine operations to transfer data streams. With a large number of ports, there can be several controllers. The more devices are connected to the branch, the higher the current load on the controller. And after reaching a certain value, a banal power shortage begins, manifested in failures, failures of connected devices and even the failure of the controller due to overload.

By the way, a USB cable purchased on the market for pennies, by means of which a "powerful" device is connected, can have a significant internal resistance, which worsens the power situation. The connected peripheral component may simply not work properly due to the loss of voltage in the conductors of the defective cord.

Therefore, if, for example, the USB port of the printer does not work, you need to make sure that the communication cable of the appropriate quality is used, and that there is no other device connected to the next connector on the board. So, almost certainly there will be problems due to power supply, if a printer is turned on in one port, an external DVD (without its own unit) is in the next one, well, and in the third one a Wi-Fi transmitter or, worse, a hard disk is working.

How to overcome the current limit

"To force" the controller to pass through a current greater than the one to which it is calculated, is impossible. Therefore, if peripheral USB devices fail, you can go in several ways:

- distribute the components to different controllers, that is, connect the printer to another connector that is adjacent to the empty one;

- attach the most "voracious" devices to USB 3.0 ports;

- use an external hub with active power. This device is an analog of the tee for the electrical network (branched lines). It is connected to the free USB connector of the computer, it is powered by its own source, and all other peripherals are included in the ports on the hub. Very convenient solution. The disadvantage is that you need a free outlet and additional money to buy.

The driver is not a luxury ...

Now on the market there are many boards, in which, in addition to USB 2.0, there is a newer standard - 3.0. And, although it is indicated about backward compatibility of versions, this is not completely fulfilled. The USB port device is such that it is necessary to install the driver in the operating system. One time. This is a mandatory requirement. Thus, if the owner of the computer connects the USB 2.0 device to the port of the third version, but at the same time forgets to install the management software package for support, then no one can guarantee normal operation.

Problems with contacts

There are four spring-loaded copper tabs inside the USB bus plugs. It is thanks to them that they come into contact with the pads in the connectors. With frequent use, the contact is broken and malfunctions begin. To solve the problem, you need to return the arc of bending the tabs with the help of a needle or replace the interface cable with a new one.

Cleaning inside and outside the system unit

Very often the computer looks clean, but inside the case there are whole deposits of dust. Connector ports are also contaminated. Household dust does not conduct current. Therefore, if the USB port has stopped working, you need to clean the connector carefully, blowing out dust with a syringe. It must be remembered that external and internal purity are different things. The system unit requires periodic revision with cleaning and purging.