PSU Won’t Turn On When Connected To Motherboard: A Full Guide!

You build a PC, press the power button afterward and it doesn’t turn on. There it is. The nightmare begins. 

Most of the time, a PC not turning on depends on the power supply unit. But when your PSU turns on but not with the motherboard, it becomes worrisome. 

What are the solutions when the PSU won’t turn on when connected to a motherboard? 

When the PSU won’t turn on you’ll have to check the motherboard connections. Faulty PSU connections can interrupt the bootup process. Besides, you’ll have to check the front panel connectors. Many users often misplace them accidentally. It’s also possible that the power cable has been damaged. 

Anyways, we briefly talked about the solutions here. Obviously, these aren’t enough and each of these fixes requires more elaboration.

Luckily for you, we’re more than happy to provide it to you. Stay with us till the end if you want to know about PSUs and motherboards. 

PSU Doesn’t Turn On While Connected To Motherboard: 3 Possible Reasons & Solutions

Computer problems are super frequent and they can be really annoying at times. PSU not turning on is one of those issues. Here’s someone who faced similar issue with a brand new PSU!

One such problem is failing to turn the power supply on. It’s one of those frustrating problems because you don’t know what’s causing the issue. 

Motherboards creating clicking noises is also a similar problem. Both problems require thorough checking of multiple components one by one. 

PSU motherboard compatibility is an extremely rare issue but it can happen. Since most of the PSU is ATX standard we will ignore it. 

Other than that, many users complain that their PC won’t turn on with new PSU. Sadly there can be many reasons; both from PSU-end and motherboard-end. 

That’s why we’ll be checking PSU motherboard pins in some of the procedures. Also, you may not know everything about PSU motherboard connectors. 

In that case, you can easily look them up on the internet. 

But often most people wonder, why won’t my PSU turn on? 

Your newly connected PSU may not turn on because of a poor connection. It’s also possible that you may have misplaced the front panel connectors. Other than that, a bad or damaged power cable can be a viable culprit. In a worst-case scenario, your PSU may have died. 

We have talked about these problems one by one in detail. We have also provided solutions right after. This way you can easily identify possible problems and start working on them!

With that being said, let’s not waste any more time and head right in-

Problem 1: Faulty PSU Connection Interrupts the Booting Process

Motherboards not turning on the power supply occurs often due to bad PSU connections. That’s why we have discussed this before everything else. 

In many forums, the users have stated that their power supplies turn on just fine. But when connected to a motherboard, all the hells break loose. 

That’s why you’ll have to go through all the connections thoroughly.

Solution: Check the Power Supply Connections

There are about 8 types of power supply connectors. Failing to connect even one of them properly will result in a faulty connection.

That’s why it’s a must to know about those connections. For a better understanding, you can get your PSU manual. They contain different power supply pins and PSU connector diagrams. 

Motherboard manuals can also help you understand what connectors to use in what sockets. 

Start with the 24-pin ATX power connector. It’s the biggest connector of all the power supplies. Because of that, it’s quite hard to plug in and plug out.

Make sure the 24-pin ATX power connector is plugged in firmly.

It can also be a 20-pin ATX power connector. These connectors will have an attach option and you can hook in 4 more pins. 

They are set up as 20+4 pins and you can detach them as well. If your motherboard has 20-pins, separate the 4-pins before attaching the power connector. 

After that, check the 4-pin ATX +12V power connector. These connectors are used to power the CPU. Needless to say, without this connector, your CPU won’t boot up. 

When you’re done, take the 8-pin EPS power connector and connect it to your GPU. For higher-end GPUs, you’ll need to connect multiple 8-pin EPS power connectors.

I have an MSI Gaming GeForce RTX 3080 in my PC system. It has 3x 8-pin EPS power sockets. 

Other than that, you have some SATA power connectors and Molex connectors. SATA power connectors provide power to HDDs and SATA SSDs.

As for Molex connectors, they’re mostly used to power up the case fans. They’re also used for air coolers. 

Make sure these two types of connectors are correctly attached. When you’re done, boot up the computer and your problem should be solved.

Unlike, regular and semi-modular PSUs, fully-modular PSUs require manual connections. In easy words, you’ll be connecting both ends of the PSU connectors.

Because of that, you’ll have to make sure you’re using the correct PSU connector slots. 

Fully-modular power supply units come with multiple cables of similar pins. That’s why it’s possible to connect different power cables to PSU and motherboard. 

That’s why it’s best to connect the power cables to the motherboard first. Afterward, you can route them up and connect them to the PSU. 

Problem 2: Misplaced Front-Panel Connectors Will Prevent PSU Start-Up

Unplugged or misplaced front panel connectors are often the main culprits. 

They’re frequently responsible for PSU not working with motherboards. 

Every system needs a power button. After all, without a power button how are we going to start a process? 

The front panel of your PC casing has a built-in circuit. Wires connected to that circuit need to be attached to the right switch inputs. 

Without that, your motherboard won’t even turn on. And because of that, it feels like your PSU isn’t turning on.

Solution: Check the Front Panel Connection

Motherboards have multiple inputs for front panel connectors. They are the power switches, power LEDs, reset switches and HDD LEDs, etc.

Without a correct power switch connection, the motherboard won’t boot up. If you fail to connect the reset switch, the restart button won’t work too.

Get your motherboard manual and head to the power section. They’ll have a full diagram drawn for you. If you don’t have it, that’s alright. 

You can also find the diagram on the motherboard itself. They’re mentioned as PWR SW, PWR LED, etc. 

Start by taking the Power SW cable and hooking it to the PWR SW input. When you’re done, take the Reset SW cable. Connect the cable to the inputs that are mentioned as “Reset”. 

You’ll also see PLED+ and PLED- inputs. They’re side by side so match the + and – first. Attach the PWR LED cable to these ports. 

All that’s left is to connect the HDD LED cable. Insert the cable to the correct input and you’re all done!

Now that you’ve done it, start up your computer. Your PSU should boot up just fine!

Problem 3: Used Power Cable Can Be Damaged

Power cables that you connect to the wall socket can be damaged. It can happen if the power cable has been used for a long time.

There are different kinds of power supplies in the market. The most common ones are 450W, 550W, 650W, and 750W PSUs. 

Solution: Replace the PSU Cable

Although most PSU cables are identical, they aren’t exactly the same. Their pin qualities and voltage tolerance can differ. 

On top of that, a PSU power cable can be damaged over time. When that happens, you’ll have to replace the PSU cable. 

But you may want to eliminate the possibility first. But to test that, you’ll need an identical PSU cable. If you have friends or stores nearby, you can borrow such cable to test it. 

That’s why it’s best to use the cable that came with the PSU. But you may not have access to the power cable itself. In that case, you’ll have to get a new one. 

Speaking of power cables, here’s what our experts recommend-

These cables are compatible with most power supplies. You can safely choose any of them and get them plugged in!

It’s also possible that your power supply has died due to an unfortunate event. In that case, you’ll have to check the power supply itself. 

Luckily, checking whether a PSU has died or not is super easy. It only takes a couple of minutes and you can do it by yourself. 

Frequently Asked Questions (FAQs)

How do I know if my PSU power supply is failing?

A failing power supply will show multiple symptoms at times. Your PC will fail to boot up sometimes. You’ll also notice a couple of random restarts here and there. Besides, you may hear some loud noise coming from the power supply. Other than that, you may encounter random blue screens of deaths. 

What is the lifespan of a PSU?

The average lifespan of a PSU is around 5 to 10 years. But it mostly depends on the components that have been used. Some power supplies have a warranty of 5 years and some have 10 years. Power supplies with high-quality capacitors tend to last for a long time. It can also depend on the PSU rating. 

What happens when a PSU dies?

A dying PSU will start to heat up from the inside. They can also melt the materials of your power cable. When these happen, you’ll have to replace the PSU immediately. Although these incidents are less likely and don’t happen as always. In most cases, your PC will simply not boot up. 

Take Away

That was everything we could explain on PSU won’t turn on when connected to motherboards. Hopefully, this discussion and the fixes mentioned have solved your problem.

If you’re still struggling to turn on your PSU, take it to a repair shop. They have experts and they’ll easily find the problem in your PC.

Finally, have a nice day and happy gaming!