There is a lot of discussion around the choice of processor, video card or motherboard, but few people know that without a good power supply all this will not work correctly. This part converts incoming voltage and distributes to all elements of the computer. In the event that the "machine" does not turn on, the first step is to check the PSU.
How to test the power supply of the computer
The power supply failure is extremely rare, because all modern models have protection against power surges, overloads and other network problems that could disable it. However, in case the computer does not turn on, the first place is not the processor check, but the task to test the power supply. As a rule, in case of problems with it, the system unit does not give any signs of life: there is no rotation of the fans, noise from the hard drive or the motherboard.
To conduct a power supply test, you must turn off the computer, on the back panel of the PSU switch the toggle switch to the "off" position. For convenience of work, the part must be removed from the system unit. Typically, the power adapter has the format atx, which is standard for most models of cases, and a set of cables for the motherboard, video card, cooler, hard drive. They should be checked first for service.
Power pin plugs for
The computer checks for operability by having power to all elements of the system. To test the pin power connectors, the PSU must be switched on, but for this it is not necessary to connect the part directly to the motherboard or anything else. To do this, enough paper clips, which will close the chain or cooler, the main thing is that the power supply does not work "idle".
If you connected a cooler, then you can not be afraid to turn on the power supply. In the instructions or on the packaging, and often on the body of the device, it is written what voltage should be applied to the line. Using a multimeter, you can check each one for compliance with the declared indicators. If somewhere the power does not match or the indicator is completely absent - this is the place where the BP breaks down. This method will be described in more detail in the method of checking the power cord of the
motherboard. Power cable for the
computer. In some cases, not one of the power supply cables but a power cord that causes voltage to the device become the cause of the breakdown. It can break at a long time in the wrong position, burn in places of bare wire, etc. To replace this element of the system is the easiest, so when you test the power supply of the computer, you simply try to turn it on. To do this, you need:
- Connect the cooler as described above to load.
- If there is no cooler, then on the 24Pin( atx) cable you need to close two contacts.
- Locate the green wire and black that will need to be closed.
- Take an ordinary paper clip, unbend it to get the letter U.
- Insert one end of the paper clip into the place of the green wire, the second - into the black wire. This will tell the PS that it is connected to the motherboard, and will allow you to turn on.
- After this, you can turn on the device.
- If the cooler of the device started spinning, then the power is supplied to it, and it's not the power cord.
- If it does not, then the cable or some part inside the power supply of the computer is defective.
Power supply of the
motherboard For verification, you will need a 24Pin( atx) format cable that connects to the motherboard. Find it is not difficult, it is the largest and has 24 pin contacts( old 20).It already has a paper clip attached, if you have not connected a cooler. All the wires of this cable are painted in a different color, not for beauty sake, they indicate specific indicators. Colors mean the following:
- black - earth;
- orange - + 3,3V;
- red - + 5V;
- yellow - + 12;
- green - PS ON( paired with the "ground" starts the PSU, so they close the clip);
- gray - + 5V;
- purple - + 5V;
- white - -5V;
- blue - -12V;
These values may vary slightly depending on the manufacturer, brand of the computer power supply, but most devices meet the above specifications. To check the wires, you need a multimeter. One probe( minus, black) is necessarily connected to the black wire, and the second( red) to the contact being checked. You must compare the stated voltage( in colors) to the actual voltage. If there are significant differences somewhere, the cause of the incorrect operation of the PSU can be served by this wire.
Testing the capacitor with the multimeter
The main task of this power supply unit element is to maintain, support the electric charge and smooth the voltage in the electrical circuit. For example, all watched the "blinking" of light, which in fact is a short-term voltage drop in the network. Power units with faulty or bad capacitors can not withstand such moments, the computer restarts. Good at the same time release the accumulated energy and provide sufficient voltage to continue the system. You can check the capacitor as follows:
- To test the capacitor, you need to set the multimeter to the "ringing" mode.
- If there is none, then measure the resistance with the set value of 2 Kiloom.
- Connect the black probe to the negative terminal of the capacitor, and the red probe to the positive terminal. If you confuse, then nothing terrible will happen, but you will not be able to check it.
- If everything is done correctly, the capacitor will start charging. The indicator should be above 2M, which indicates the sufficient capacity of the part and its serviceability. At a reading below or equal to 2M, the capacitor must be replaced.
How to test the resistor with the multimeter
The above describes in detail how to check the cables of the computer power supply, but the breakdown does not always lie in them. Sometimes the cause of the failure are smaller parts, for example, resistors. The burned out detail can be detected with the naked eye, but at times the problem lies in the incorrect resistance. To check, you need:
- Switch the multimeter to the resistance measurement mode.
- View the nominal value either on the resistor itself, or on the board next to it. If there is no such data anywhere( Chinese manufacturers apply colored circles), you can set the value to 2000 ohms and if it is exceeded, just the figure 1 appears.
- Set the black probe to "minus" and the red one to "plus" the resistor.
- If the nominal and actual resistance do not match, the part must be replaced.
- Deviations of 5% are permissible.
Program for testing the power supply of the computer
How to check the power supply of a computer with a multimeter is understandable, but there is an option without having to remove it from the system unit. You can download a program with which you can check the PSU.They use it, as a rule, with spontaneous shutdowns, reboots, "blue screens of death".Before manual diagnosis it is important to understand what exactly causes such malfunctions. In some cases, the cause is the processor or driver. For verification, you can use the OSST program.
This software creates the maximum load on this or that element of the system. It is not recommended to use the program on cheap, weak systems. Inside it there are several tabs that relate to the processor and memory, video card and PSU.The load on a particular element will help determine the problem with it. You need to do the following:
- go to the tab "power supply";
- set the resolution corresponding to your monitor;
- type of test - "manually";
- the duration of the check is 1 hour;
- complexity of shaders is the optimal parameter that the program offers;
- put a tick in front of the windows "fullscreen", "hypertrading", "64 bit Linckpad";
- press the "ON" button.
If during the test failures occur, the program compiles a report on the errors that have arisen, indicates their nature, which allows working with specific problematic elements of the computer. This becomes a serious reason for extracting the BP and manual detailed verification using a multimeter. Remember that with self-analysis of the details of the warranty from the manufacturer are removed.