The motherboard and CPU are the heart and soul of your computer system. 

They enable your computer components to connect and enable all the processes that make your computer work efficiently.

The motherboard is the hub for all the circuit boards that connect the system parts together. Your computer’s main drive sits inside the motherboard.

The CPU connects to the motherboard. It sends signals to the computer’s memory,hard drives and other critical parts that make your computer work.

When the CPU fails, it may mean the system could be overheating or some inner connections may be loose.

A bad motherboard may cause the system to keep rebooting at odd times, or the system may crash altogether.

Motherboard
Computer Motherboard

Other causes of motherboard and CPU failures

When the motherboard breaks down or fails to boot up, there may also be a number of reasons.

Some other signs of computer failure may include: 

  • Faulty or bulging connectors
  • Burning on the motherboard or smells of burning when the computer is running
  • Not enough power supply or voltage
  • Imbalances in the computer’s internal cooling system
  • Peripheral connectors may sometimes flash on and off
  • Your computer is not reading your flash drives properly

While these issues can be daunting, there are some simple steps you troubleshoot at home using a multimeter.

A multimeter helps you get the correct measurement of your system’s resistance, voltage, and electrical current.

Here are some areas to check to see exactly what’s happening inside our computer system.

1.Check the voltages

First, check to ensure the connections to the ATX pin and the AC power are in place.

Adjust the setting on a multimeter to read at least 20V of direct current.

Next, examine the exterior of the connector using the black multimeter probe.

Connect the black probe to the GDB Pins 15, to 17.

2. Test the purple and green measurements

Test pins 9 and 14 with the red multimeter probe.  Check for the measurements as follows:

  • Purple, VSB Pin 9 – should read at least 5 volts.
  • Green, PS on – Pin 14 voltage measurements should fall between 3 and 5 volts.

Turn on the PC’s power switch and let the PS_On value fall. If the value drops to any measurement besides O, it may mean there is a problem with the switch.

3. Troubleshoot Pin 8

Examine the gray, Power_Ok or Pin 8 switch with the red multimeter probe.

The measurements must read above 2 ½ volts and will indicate your system can start without any issues.

Next, reset the Pin by pressing the Power_Ok switch.  The volts will fall to zero, and then gradually rise to the normal levels.

How to test the motherboard and PSU for any circuit issues

1. Disconnect the computer from the AC current. Leave it for a few minutes to let the charge run out.

Adjust the multimeter to about 200 Ohm and connect the probe leads to set the meter to zero reading.

Connect both lead probes to the metal on the system’s chassis and ensure the reading also stays at zero.

2. The “On” and “Off” switches on your computer may also be faulty at times. Faulty switches may cause the system to break down.

Most computer systems operate by an ATX power source. The ATX current helps keep your motherboard running, even when the computer is switched off.

Take out the ATX connector from the motherboard. Hold the multimeter black probe onto the chassis metal plate.

In some cases, the power switch may have 2 or 4 wires.

To check the system with 2 wires, unplug the computer and use the multimeter’s probes to both wires.

Press the switch until the resistance starts to drop.  Any resistance reading close to zero means the switch is working well.

Using the red lead multimeter probe, measure the volts on the direct current connector with the black wire pins.

Ensure each voltage has a zero reading.

If the switch has 4 wires, they will be distributed in clusters of two’s. They may also fall to the right and left of the motherboard, or they may sometimes be crossed.

First, unplug the computer. Test each wire cluster separately. Insert the button until the resistance readings fall to zero.

3.  Check the colored wire readings

Hold the black lead probe on the metal chassis.

Examine the readings of the colored pins of the direct current (D/C) connector using the red multimeter probe lead.

4. Detach the CPU from the motherboard slot. Measure the pin numbers on the motherboard’s connector using the ATX 20-Pin chart guide.

Rest the black multimeter probe onto the chassis metal plate. Test the GND pins with the red multimeter lead.

Ensure Pins 3, 5, 7, 13, and 15 to 17 on the motherboard’s connector have a zero measurement.

If the reading is showing a number more than zero, it may mean there is a problem with the connector.

Check the connectors

Your motherboard also has connections on the edges of the system that ensure power reaches your hard drives and CD-ROM drives.

Each connector has four pairs of wires (8 wires) located to the left and right sides of the motherboard.

They are in colors of red, yellow and black.

To troubleshoot for any faulty connectors, connect the black multimeter probes to the black wire, and the red probe to the red wire.

Each wire should have at least +5 volts of direct current.

Next, run a similar test by connecting the red multimeter probe to the yellow wire and the black probe to the black wire.

Ensure there’s a reading of at least +12 volts of direct current.

If any of the readings do not match up, there may be a faulty power supply or an overloaded periphery connection.

To test for normal voltage readings, detach all the connections and run the test again.

If the voltage falls within the normal ranges, use fewer peripheral connections or increase your watts of power.

If there are lower than normal voltage readings, you may need to disconnect and replace the power supply. If you feel interested to test a computer motherboard and CPU for failures at home first you should buy a multimeter and check outfor best budget multimeter on the browser and gain ideas on buying it.