A PSU (Power Supply Unit) may not be an exciting PC component, but it's among the most — if not the most — crucial parts as it brings the entire PC to life. Not only is it important to pick the right PSU for your PC, but you also need to ensure it's installed properly. Installing the PSU is fairly simple, but getting all the connections right and managing the cable is more time-consuming. Replacing or changing the PSU is also a bit more complicated as it involves dealing with the existing components and their corresponding connections.

How to remove your old power supply unit from the PC case?

Don't forget to remove all the cables

The first thing you need to do is remove your old power supply from the case. To do this:

1. Start by switching off the PSU by flipping the power switch to the off position.
2. Unplug all cables connected to the back of your computer/motherboard IO panel, and remove both side panels of your case to access the PSU easily.
3. Unplug all the power connectors that lead to the PSU from different components

   It is recommended that even those with a fully modular PSU remove the old cables entirely and use the new ones that come with your new PSU, so unplug them from the motherboard, too.

4. (Optional) Take a picture of all the connections to help you remember where all the cables lead.
5. Remove the screws that hold your power supply unit in the case. You'll typically find two to four screws, so take them off and set them aside safely.
6. Pull your old power supply out of your case after unplugging and unscrewing all the connections. If your case comes with a PSU shroud or an enclosure, you must remove it to take the PSU out.

How to install a power supply unit in your PC case

Make sure you get the connections and cable management right

Assuming you have the new power supply unit ready for installation, follow the steps highlighted below to get it up and running:

1. Start by inserting the PSU into the exact position of the old unit. You may have to take out the PSU shroud or the enclosure and drop the PSU in it if your PC case comes with one.

   You can plug all the necessary cables into the PSU before securing it inside the case, but you can also do it after.

2. Secure the PSU in place by tightening the screws.
3. It's now time to start wiring things up, so start by plugging cables into the PSU if you haven't already.
4. Feed the cables in from behind your motherboard, and use the cut-outs on the case to pull each connector through, exposing only the necessary cable next to its connector.
5. Ensure you get all the connections right, like the 24-pin and 8-pin motherboard and CPU power connectors. You can refer to the picture you grabbed earlier to get all your connections right.
6. Plug all the PCIe connectors, SSDs, and hard drives properly, and ensure they're all securely seated. Note that you may need more than a single 8-pin PCIe connector for connecting your PSU to GPU, especially if you have upgraded to a new graphics card.
7. Lastly, it is recommended that you spend some time managing all the cables and arranging them neatly inside the case, so it's easier to find the right one should you need it. Modular power supplies make this less time-consuming than non-modular ones, but you'll need to be patient with the cables either way.
8. Plug everything back into the motherboard IO, flip the PSU power switch on, and see if everything works properly before securing the side panels back in place.

And that's how easy it is to change your old PSU with a new one. All the steps highlighted in the sections above may seem daunting, but it's a fairly simple process that'll only take a few minutes to an hour if you get everything right.

Installing the PSU is a simple task that seems complicated

Changing the power supply unit of your PC is not as complicated as it looks, and it mostly depends on how well you've routed the cables inside your case. This is why it's crucial to spend some time managing the cables. Cable management is known to be the least interesting part of a PC build, but it's times like these when you realize how important it is. A modular power supply saves you a lot of time and hassle, too, so try to get your hands on one of these if your budget allows for it.