How to test a laptop motherboard with a multimeter

How to test a laptop motherboard with a multimeter

During my 30 years as a computer technician, I’ve found the motherboard to be one of the most difficult parts to fix. This is due to the fact that it consists of a large number of components.

Some of the symptoms of a faulty motherboard include: blue screens of death; computer lockups; inability to locate USB storage devices or other hardware; and the list continues. You will learn how to test a motherboard with a multimeter before it is assembled with other PC components in this guide.

Tools required

In order to perform a motherboard diagnostic test, you’ll need the following supplies.

Identifying and repairing motherboard problems

First, you should conduct a POST (power-on self-test) to ensure that your new motherboard works and that you didn’t receive a dead on arrival (DOA) motherboard (dead on arrival).

How to tell if the motherboard is working is as follows:

  • Use a non-conductive surface, like a wooden table, to place the motherboard.
  • Thermal paste should be applied to the processor once it has been installed.
  • Connect the CPU cooler to the motherboard, and then to the CPU..
  • Put at least one RAM module in the place indicated (DIMM 1).
  • Connect the GPU to the motherboard and, if necessary, to the power supply. Find out by reading the instruction manual for your GPU.
  • Plug in the power supply’s 24-pin ATX connector to the motherboard.
  • If you want to use the monitor as your primary display, connect it to the HDMI port on the GPU or the integrated graphics card.
  • Ensure that the power supply’s cord is plugged into a surge protector or an outlet.
  • Use a jumper to turn on the computer. It is possible to complete the power circuit illustrated above without the use of a voltmeter.

Turn off the computer by shifting the switch on the power supply to the “off” position after ensuring that POST worked.

You’re good to go if the computer boots into the BIOS. Put the motherboard back in its case, disconnect everything, and then put it all back together. It’s possible that your motherboard didn’t POST, and if that doesn’t work, contact the manufacturer and request that they send a replacement.

How can you tell if a motherboard has been damaged or is working properly?

When it comes to computers, motherboards are among the most difficult parts to diagnose. When motherboards fail, they are usually rendered useless. To make yourself feel better, follow these simple steps.

  • The Power On Self Test, or POST, is done every time you switch on your computer. Go to the startup section if your machine is operating normally. If you can’t complete POST, continue on to the next step.
  • Determine whether or not your motherboard is shorting out because of your casing. The standoff screws within the casing must be placed precisely.
  • Make sure your computer isn’t overheating. Open the case and inspect the fan, components, and motherboard for dust. Compressed air can be purchased at your local hardware shop and used to clean the area.
  • A beep code will sound whenever your computer is powered up. You can use these beep codes to figure out what’s wrong with your device. Beep codes and their meanings are shown below.
  • Download and install any necessary BIOS updates from within the BIOS. Restart your computer after restoring or restarting your BIOS to restore all settings to their default levels.
  • The CMOS battery should be replaced if you still can’t go into the bios because your machine keeps restarting The motherboard problems should be resolved if your PC is still in BIOS after changing the battery. The diagnosis should continue if they don’t.
  • In the end, remove everything but the CPU, the cooling fan, and the RAM. The only way to figure out which component is malfunctioning is to add hardware one piece at a time, starting with your motherboard.

The best way to test a mother board with a multimeter.

It’s time to break out the multimeter if you can’t figure out what’s wrong with your motherboard using the methods described above. A hardware store near you might have one, or you could order one from Amazon. For less than $13 on Amazon, you can get a fantastic one like this.

If you have a multimeter, you’ll be able to quickly identify any faults with the motherboard. You can test your motherboard for faulty components even if you’ve never used a multimeter before, and I’ll walk you through the process step-by-step.

What is the procedure for testing the voltage of an AC current?

The first thing to look for with a multimeter is a short circuit. Electrical surges are known to cause a variety of issues. Checking the motherboard’s AC voltage is the next step we’ll do.

  • Disconnect the computer’s cords and shut it down.
  • Allow 10 minutes for the heat to dissipate and the motion to cease.
  • Use a multimeter with a low setting. 0.1 ohms or 200 ohms of resistance.
  • Make sure you obtain a reading when you touch the two wires together by touching the chassis.
  • Remove the ATX Power Connector from your computer’s motherboard.
  • Make a connection by placing the black wire on a chassis and the red on a ground pin of a power connector (any black wire). In other words, the metre should read 0.
  • Keep the black wire attached to the chassis, and use the red wire to examine all other cables for problems. Check the pinout below to make sure each voltage is correct. It’s fine if the price is slightly more. A problem exists if it’s lower than that.
A 24-pin ATX connector's standard pinout.

A 24-pin ATX connector’s standard pinout.

Remove the motherboard from its packaging. In order to locate the pins, look at this 24-pin ATX graphic. The red wire can be used for the following: This test should yield a zero (3, 5, 7, 15, 17, 18, and 19). The PSU connector is broken if you see anything else.

For the last test, you’ll need to remove the motherboard to access the ATX power adapter and CPU. Try the motherboard’s ATX pins that are identical. The motherboard’s connector is broken if the number is greater than zero.

Find out how to read the DC voltage


  • To verify DC voltages, follow the instructions outlined below. Steps differ from those for AC voltages in this scenario.
  • A 24-pin ATX cable from the motherboard to the power supply must be connected before you can use it.
  • Set your multimeter to 20 volts direct current (DC).
  • To check the back connector, connect the black wires to pins 17, 18, and 19.
  • As a rule of thumb, you should insert the red wire into pin 9 and then pin 16. Between 3 and 5 volts should be used.
  • At this point, it’s time to switch the computer on. It’s wonderful news if the numbers drop to. There is no way around it.
  • Pin 8 can be found by using the red wire once more. More than 2.5V should be shown. Check to see whether the numbers go back up when you press the reset button on your computer. The motherboard must be replaced if this is not the case.
  • Do not attempt to repair a faulty motherboard on your own. Even if the repair is successful, the inappropriate method of controlling the voltage could cause your computer to malfunction. Attempting to repair or replace the motherboard on your own is always a bad idea, and should be avoided at all costs.

How to check the RAM slots on a motherboard

  • Using the black wire when the computer is turned off, try to access the connector’s backside. In order to see a Voltage, it should be connected to one of the negative pins 15, 17, 18, or 19.
  • The red wire can be used to check and probe the following pins: The voltage on pin 16 (green) ranges from 3 to 5 volts, while the voltage on pin 9 (black) is zero (colored purple) The voltage is 5 volts.
  • Activate your computer and get ready to work. You want the voltage on Pin 16 (Green) at least to be volts. If this is the case, then the switch is faulty. This machine has been shut off.
  • Last but not least, connect the red wire to Pin 8 (grey) and check for 5 volts. Restart the computer by pressing the power button and the reset button at the same time. A reduction in voltage will occur, followed by an increase in voltage. There is a strong chance that you need a new motherboard if this doesn’t work.

What is the best way to test a motherboard without a processor?

In order to verify that the motherboard is functioning and supplying electricity to linked components such as case fans and RGB lights, you do not need a CPU. Because I’ve done it numerous times, I’m confident in my knowledge.

How do you test a motherboard capacitor?

Only by removing the capacitor from the motherboard and performing the test on a different component can it be verified. To check for oxidation, cracks, leaks, or bulge in each capacitor is possible. This will tell you if the capacitor is faulty, so you can fix it.

The answer to this question is yes.

Repairing a motherboard may be more cost-effective than purchasing a new one for an older machine. Buying a new motherboard may necessitate the purchase of a new CPU and RAM.

Is it worth it to replace the motherboard?

If your computer’s motherboard controls how much power flows through its components, it’s a very useful piece of hardware to have. A damaged motherboard could create power surges, which could harm your RAM, GPU, CPU, and other components.

What will happen if my motherboard fails?

The manufacturer should reimburse the cost of a new motherboard if it malfunctions while being opened or set up. An RMA must be requested by calling the company (Return Merchandise Authorization).

After a few years, the warranty on the motherboard will expire, and you’ll need to buy a new one.

James Hope
My name's James and throughout the long term. I have actually assembled numerous PCs for me as well as my companions. I love gaming, programming, illustrations planning and essentially whatever has to do with PCs and innovation.