How to replace PSU on MK3S and MK3

Meaning of Replace PSU?

Replace PSU is the error name that contains the details of the error, including why it occurred, which system component or application malfunctioned to cause this error along with some other information. The numerical code in the error name contains data that can be deciphered by the manufacturer of the component or application that malfunctioned. The error using this code may occur in many different locations within the system, so even though it carries some details in its name, it is still difficult for a user to pinpoint and fix the error cause without specific technical knowledge or appropriate software.


How To Install A New Power Supply

  1. Mount the new power supply unit into the computer case by using the case mounting screws.
  2. Reconnect the internal wiring from the output of the power supply unit to the hardware components inside your computer case. Be sure to refer to the notes/photos that you took in the removal stage to make sure that all the components are reconnected. Checklist for reconnection: a) Motherboard b) CPU power connector c) Hard drives, Solid state drives, Optical drives d) Any power connections needed by your graphics card  – if required (not all graphics cards models require power from the PSU) e) Fans (if applicable) f) Refer to your notes/photos of what was previously connected, and do a final check on all connectors to make sure they’re secure
  3. Close up the computer case.
  4. Plug in the input cable to the power supply. (Connects the wall socket to the power supply). If your new PSU has a power switch, don’t forget to flick it to the on position.
  5. Power up the computer and test.

There are only really two main reasons why you would need to replace the power supply unit in your computer, and if neither of these concerns you then the good news is that you can probably leave it alone.

  • Reason 1: The PSU  is dead (won’t power on) or faulty
  • Reason 2: The PSU is not fit for purpose

What do we mean by ‘not fit for purpose’?

Basically, this means that the power supply won’t reliably do what its intended to do – power your computer components safely and reliably.

PSUs that are not fit for purpose generally fall into two categories:

  1. The rated power output capacity of the PSU is too low Usually, this can happen if you are upgrading components in your computer that require more power. The rated power output of a PSU is measured in Watts, and must be high enough to supply all the components within your computer. A classic example of when the power output of your PSU may suddenly become too low is if you are upgrading other components in your computer. For example, installing a new graphics card that requires more power consumption can in many cases trigger the need to replace the existing power supply to a unit with a higher output capacity.
  2. The PSU is a cheap brand or of low quality The power supply might be cheap and you don’t trust it. Unfortunately this can be the case with many pre-built computers, as cutting the budget spending on the PSU is very common. We recommend doing a little bit of research online on your particular brand/model of power supply to make sure it doesn’t have a reputation for blowing up or failing.

How Do I Know What Size Power Supply I Should Have?

Power supply ‘size’ can mean two things, but usually refers to the output capacity of the unit (measured in Watts).

Output Capacity

The output capacity of your computer’s power supply needs to be high enough to supply enough power to all of the components inside your computer case at the same time.

Prebuilt Computers

If you have a prebuilt computer, the designers would have calculated the maximum power requirements at any one time, and sized the PSU according to that – so you shouldn’t need to worry about the size of the PSU in your computer in this case.

One thing you may have to worry about with prebuilt computers though, is the quality of the power supply. If it is a cheap/no-name brand, it may cause issues.

DIY Computer Builds

If you are building your own computer, then you need to work out the maximum power draw on your own in order to size your PSU. You can use calculators like this one to help you figure it out.

Usually, the largest power-sucking component is your graphics card if you have a dedicated one. Many graphics card manufacturers have a ‘minimum total system power’ recommendation in their graphics card specifications that can be used as a guideline to the total power supply size you’ll need if you want to build a computer with this graphics card.

The manufacturer’s specifications for the Ge
The manufacturer’s specifications for the Geforce GTX 1060 show that the minimum system power requirement is 400W. This means you’ll need to have at least a 400W power supply in your computer if you want to run this graphics card. Source: GeForce Website

Form Factor

However, be aware that ‘Size’ can also refer to the physical size dimensions of the power supply unit (this can also be referred to as ‘form factor’, which is the shape and general physical layout of a component).  Not all power supply units are the same physical size, so you’ll definitely want to be aware of this before trying to swap out one unit for another – as the worst thing that can happen is to find out that the new one won’t physically fit where you want it to!

Remember that the power supply unit is responsible for supplying power to every hardware component that makes up your computer system.

When it comes to power, there’s such a thing

When it comes to power, there’s such a thing as quality too – when we talk about power quality, it means that the power being supplied is clean, constant, and within the expected operating limits.

If you have a low-quality power supply, it may not supply a good quality power to the hardware components in your computer – which can cause performance issues, or at the extreme end of the scale, even damage or reduce the lifespan of your hardware.

Unfortunately, many manufacturers of prebuilt computers tend to spend a lot of their budget on fitting in high spec’d items like a processor and graphics card – but then skimping on the power supply.  The end result can be disastrous, just google something like ‘power supply blew up’ to get an idea of what can happen…

Caution: Output Ratings Can Sometimes Be Misleading

Cheaper brands can even tend to exaggerate their PSU’s output capacity rating (example: We’ve seen units to be a 300W power supply, but if you take a closer look, the rating is a 300W peak rating and the continuous rating may be less than this).

If you’re planning on installing a new graphics card and still using your existing power supply unit, make sure to check the output rating first. Be especially careful to check for any trick ratings on no-name brand PSUs if you are pushing the upper limits of your existing rated power supply unit. (It’s usually safer to oversize your PSU, just to be sure!).

It’s really important to make sure your power supply is decent in order to protect your other hardware components and ensure they have a long life.

80 Plus Certification

One certification to look out for is the 80+ certification, which means that the power supply is at least efficient and has less than 20% losses. While this is not specifically related to overall quality of a PSU, the fact that the PSU you’re considering buying has a certification of some sort is an indication that the manufacturers have considered quality at some level.