How To Test Motherboard With A Multimeter?

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Abdul Hadi

At HI Digital I test and write about different hardware configurations to show other PC users what they can expect from their build. My end goal is to educate the masses to make the right decision when they are looking for new PC parts to buy

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A multimeter is a digital device used to test voltages, measure current, and assess resistance in a circuit. The probes are connected to the device being tested, and the multimeter provides results for voltage, current, or resistance measurements as the current circulates through the probes. Testing a motherboard with a multimeter helps identify short circuits and other faults that may disrupt its performance or reduce its lifespan.

Signs That Your Motherboard Is Faulty

These are the symptoms of possible faults in your motherboard:

• PC and its components, like CPU or GPU, overheats often.
• PC lags at every step or produces beeping sounds.
• Facing BSOD.
• Computer is not starting despite being plugged into a power outlet.
• CPU restarts quite often and abruptly.
• Motherboard gives off a burnt smell or fails to identify components like fans.
• PC stuck on motherboard screen.

How To Test Motherboard With A Multimeter?

I only used a multimeter with probes and a screwdriver to conduct this test. First, I checked my motherboard for any short circuits and then proceeded to voltage assessment. 

For Short Circuit

If your multimeter reads 50 Ohms or above, the motherboard is functioning properly. However, a reading below 50 Ohms indicates a short circuit. I conducted further testing to identify additional faults.

1. Power Off PC: Switch your computer off and unplug it from the power source > Wait at least 10 minutes.
2. Set Multimeter: Adjust your multimeter to the lowest setting, 200 Ohms > Connect both wires to bring the meter to zero.
3. Remove Motherboard: Take the motherboard out of your system > Remove the ATX connector.
4. Connect Multimeter To Case: Connect your multimeter’s black probe to the computer case whilst connecting the red probe to the ground pin of the PSU’s AC.
5. Connect Multimeter To Motherboard: The multimeter should give you a reading of zero. Connect the red probe to colored motherboard wires without removing the black probe from the computer case.

PSU Pins Resistance Test

Refer to the ATX 20-pin chart attached below, which displays 20-pin and 24-pin connectors. It should help make things clearer on your end.

Run a test on the ground connector pins. These are also labeled as COM:

1. Connect The Probes: Connect the black probe to the computer case metal > Connect the red probe to the black pin slot. The pins are also labeled as 3, 5, 7, 13, 15, 16, 17, 18, 19, 24.
2. Verify The Reading: Check the multimeter. It should display the reading of 0 Ohms from every black slot pin.

If the multimeter displays a value other than 0, it suggests a potential short circuit within your PSU. When testing colored slots, expect a minimum reading of 50 Ohms. If the reading is lower, it could be a reason for your motherboard issues. Consider replacing the motherboard or power supply unit.

For Voltage

The multimeter is a versatile tool for voltage testing and assessing whether your motherboard functions correctly by verifying the proper voltage supply through the power connector. Follow the given steps to carry out this test.

1. Connect The Components: Take your PSU and 20-pin connector and connect them.
2. Adjust DC Voltage: Set the DC voltage range to 20 on the multimeter dial. On the multimeter, DC voltage is either identified as DVC or V-.
3. Place Probes: Put the black probes in the connector’s ground pins (You may switch between these to test all of them) > Put the red probes on pins 8, 9, and 14.

Pin 8 should supply power of more than 2.5V to turn your computer on. After pressing the reset button, 2.5V should drop to 0V, then jump back to 2.5V. The multimeter should give pin 9 a value of 5 and pin 14 a value between 3-5V. The pin 14 value should also drop to 0V when switching on the computer.

What Might Cause Issues In The Motherboard?

Consider all these possibilities so that it’s easy for you to find the solution to the cause of the issue.

• Dusty Components.
• Overheating.
• Abrupt Contact With Hard Surfaces Or Liquids. 
• Manufacturing Fault.

Final Thoughts

This test helped me figure out what part of the motherboard has an underlying fault and is keeping it from running properly. Thanks to this simple method, I did not have to go through the hassle of going to a tech shop and could test the motherboard effectively. Additionally, buy a good-quality motherboard, such as MSI MPG Z790 Carbon Max WiFi Motherboard, to avoid frequent troubles.

Abdul Hadi

[How-To Guides Expert]

Laiba, our tech guru at HI Digital, simplifies and crafts How-To Guides with a Google IT Support Certificate. Beyond tech, she captures the city’s aesthetics through her lens. Join her journey where tech meets creativity!

Get In Touch: Laiba@hidgt.com