How to check computer power supply

A lot of discussions around the question of the choice of CPU, graphics card or motherboard, but few people know that without a good power supply it will work correctly. This part converts the input voltage and distributes to all the elements of a computer. If the machine is not activated, you first need to check the PSU.

How to test the computer’s power supply

Power supply

The PSU failure is extremely rare because all modern models are protected against power surges, overloads and other network problems that could incapacitate him. However, if you do not turn on the computer in the first place is not a test of the processor, and the task is to test the power supply. Normally, when the problems with it system unit shows no signs of life: none of the fan speeds, the noise from the hard drive or the motherboard.

To test the power supply, you must turn off the computer on the rear panel of the BP switch the toggle switch on position «off». For ease of carrying of the work item to retrieve from the system unit. Typically, the power adapter atx standard for most types of cases, and a set of cables for the motherboard, graphics card coolers, hard drive. They should be checked for serviceability first.

Pin power connectors

Check computer for performance starts with having the supplying power to all elements of the system. For testing pin power connectors the PSU will definitely need to include, but not necessarily for this item connect directly to the motherboard or something else. This is enough clips that complete the circuit or of the cooler, as long as the power supply didn’t work «in vain.»

If you connected the cooler, you are not afraid to turn on the PSU. In the instructions or on the packaging, and often on the body of the device is written, what voltage must be supplied on the line. Using a multimeter, you can check each for compliance with the indicators. If the power indicator does not match or no – this is a place of breakage of BP. Read more this method is described in the method check the power cable of the motherboard

Power cable for computer

Types and schemes of cables

In some cases, the cause of failure becomes one of the PSU cables and the power cord which supplies voltage to the device. It can be broken with a long stay in the wrong position, to burn in locations exposed wire, etc. to Replace that element of the system easier, so when checking the power supply for the computer just trying to turn. To do this:

  1. Connect the cooler as described above to load.
  2. If there is no cooler, 24Pin (atx) cables it is necessary to short two contacts.
  3. Look for a green wire and a black that will need to be close.
  4. Take an ordinary paper clip, straighten it to form the letter U.
  5. One end of a paperclip insert the green wire, and the second in the black wire. This will tell the PSU that it is connected to the motherboard, and will allow you to join.
  6. You can then switch the unit on.
  7. If the cooler device began to spin, then power is supplied to it, and it’s not the power cord.
  8. If not spinning, then a faulty cable or a component inside the computer power supply.

The motherboard

To check need the cord format 24Pin (atx), which connects to the motherboard. Find it is not difficult, it is big and has a 24-pin contact (old 20). It already has a clip, if you haven’t connected the cooler. All the wires of this cable are painted in a different color not beauty’s sake, they point to specific indicators. The colors mean the following:

  • black – ground;
  • orange – +3.3 V;
  • red – +5V;
  • yellow – +12;
  • green – PS ON (paired with «earth» starts a BP, so it closes the clip);
  • grey – +5V;
  • purple – +5V;
  • white – -5V;
  • blue – -12V;

Cords for connection to the motherboard

Depending on the manufacturer, brand of computer power supply these values may be slightly different, but most devices comply with the above characteristics. To check the wires going to need a multimeter. One probe (negative, black) necessarily connects to the black wire, and the second (red) – checks the contact. You should to compare the declared voltage (by color) with actual. If somewhere there are significant discrepancies, the cause of incorrect operation of BP can serve this wire.

Check capacitor with multimeter

The main objective of this element of the power supply is to preserve, support electric charge and smoothing the voltage in an electric circuit. For example, all observed «blinking» of light, which is essentially a short-term drop in voltage. The power supply is faulty or bad capacitors in such moments can not stand, the computer restarts. Good at this point release the stored energy and provide sufficient power to continue operation of the system. To test the capacitor as follows:

  1. To check the capacitor you need to set the multimeter to the mode of «calls».
  2. If not, the measurement of the resistance exhibited a value of 2 kilo Ohm.
  3. The black test lead and attach to the negative leg of the capacitor and the red to the positive. If messed up, then nothing bad will happen, but test will fail.
  4. If done correctly, the capacitor will start charging. The figure should be higher than 2M, which indicates that there is sufficient capacity parts and it works. When the indicator is below or equal to 2M, the capacitor must be replaced.

BJ for PC

How to check a resistor is using a multimeter

Above is described how to test the cables of the power supply of the computer but the failure does not always lies in them. Sometimes the cause of the failure becomes finer details, for example, resistors. A burned piece can be detected with the naked eye, but sometimes the problem lies in incorrect support. To check you need to:

  1. Insert a multimeter in the ohms.
  2. To see the nominal value of the resistor or on the Board next to him. If there is no such data (Chinese manufacturers apply colored circles), it is possible to set a value of 2000 Ohms and if it is exceeded, will simply show the figure 1.
  3. Set the black test lead to «negative» and red for «plus» resistor.
  4. When the divergence of the nominal and the actual resistance of the part must be replaced.
  5. Deviation of 5% is acceptable.

Program to test computer power supply

How to test computer power supply with multimeter it is clear, but there is an option without removing it from the system unit. You can download a program with which you can test the PSU. Use it as a rule, spontaneous shutdowns, reboots and «the blue screen of death». Before hand diagnosis it is important to understand what causes such failures. In some cases there is a CPU or driver. To check you can use the program of the CFC.

This software creates the maximum load on a particular element of the system. It is not recommended to use the program on cheap, weak systems. Inside it has several tabs that relate to processor and memory, graphics card and PSU. The load on the particular element will help to determine the problem with it. Need to do the following:

  • go to the tab «power supply»;
  • put fit your monitor resolution;
  • the test type to «manual»;
  • audit duration – 1 hour;
  • the complexity of the shaders is the best option that offers the program;
  • put a checkmark in the Windows «full screen», «HyperThreading», «64 bit Linckpad»;
  • press the «ON»button.

Programa SCR

If during the test failures occur, the program reports errors, indicating their nature, which allows to work with a specific problem elements of the computer. It becomes a major basis for withdrawal of BP and manual detailed checking with a multimeter. Remember that when you apply the solution details of the warranty obligations of the manufacturer are removed.

Video: check power supply unit PC