9 Ways How to Fix 3D Printer Power Supply Not Working

Some people have issues with the power supply not working on their 3D printer, which means they can’t 3D print. I decided to write an article detailing how to fix this troublesome issue.

You can fix a faulty power supply by replacing its blown fuse, checking and re-seating its connections, and setting the correct voltage. You can also fix this problem by troubleshooting the printer’s power cable and your wall outlets. If all of these fail, you’ll probably have to replace the power supply.

In this article, I’ll take you through how to apply these fixes to your power supply. So, stick with me, and your power supply should be up and working in no time!

Let’s dive in!

How to Fix 3D Printer Power Supply Not Working

Like most electrical components, the power supply unit (PSU) can be plagued by the occasional gremlin. This will lead to your printer not coming on at all, as its components need the voltage from the power supply to run.

Here’s how you can fix these issues:

1. Ensure the Wall Outlet Works Properly
2. Plug The Printer Directly into The Wall Outlet
3. Test Your Printer’s Power Cable for Continuity
4. Make Sure You Select the Right Voltage on Your Printer’s PSU
5. Check The PSU Terminals For Loose Connections
6. Ensure the Wires are Connected to The Right Terminals
7. Check and Replace the PSU’s Fuse If It’s Blown
8. Check the Power Supply’s Internal Components
9. Replace the Power Supply

1. Ensure the Wall Outlet Works Properly

The first step to troubleshooting a faulty power supply is to check the wall outlet. If the outlet is defective, it won’t deliver any power to the machine.

Plug your printer directly into the wall outlet to see if it comes on. If it doesn’t come on, test the wall outlet using other appliances like fans or lamps to see if it works with them.

If they work, the power outlet is fine, and you can move to the next troubleshooting step.

2. Plug The Printer Directly into The Wall Outlet

Sometimes, the fault can be in the surge protector, stabilizer, extension cord, etc., between the wall outlet and the printer. Removing them can result in the printer working again.

So, remove these electronics and plug your printer directly into the power outlet  to see if the PSU comes online. If the PSU works, then you might have to check your extensions and surge protectors to see which one is faulty and replace them.

3. Test Your Power Cable for Continuity

Testing your 3D printer’s power cord for continuity lets you determine if the cable has any break or fault. If you find any fault that prevents the cable from taking power from the outlet to the printer’s power supply, you can easily replace the cable.

You can test your power cable using a multimeter. You can get the versatile AstroAI Multimeter from Amazon.

It is affordable, very easy to use, and produces very accurate readings. You can use it to measure AC/DC voltage, current, and resistance.

Here’s how you can test for continuity:

• Take your multimeter and set it to the resistance or continuity test mode.
• Place one probe on the ground pin of the plug and place the other probe on the other ground pin at the other end of the power cable.
• It should read some resistance. If no resistance shows, you have an open circuit, and the wire is bad.
• Do the same for the remaining two plug terminals.
• Next, set your multimeter to the voltage section. Plug in your cable and measure the voltage between the positive and negative terminals.
• It should correspond with your country’s voltage.

You can follow this video if you need a visual guide on how to do it.

4. Make Sure You Select the Right Voltage on Your Printer’s PSU

Selecting the correct voltage for your 3D printer’s power supply can fix its issues and make it work properly again. Choosing the wrong voltage can result in really bad problems like a blown power supply or fuse.

So, check to see if the proper voltage is selected on your printer. Most printers have a switch on the side of their PSU that shows the voltage the printer is currently running on.

Check the switch and make sure it is on your local voltage setting. If you live in the USA, you should select 110V. For the UK, you can use 220V.

5. Check The PSU Terminals For Loose Connections

Checking and re-seating any loose connectors at the power supply’s terminals can get it up and running again. If the wires bringing in power aren’t making proper contact with the terminals, the power supply will not work. So, make sure the wires are seated and clamped down properly.

NOTE: BEFORE YOU DO THIS, MAKE SURE YOU TURN THE PRINTER OFF AND DISCONNECT IT FROM ANY OUTLET.

To do this, open the printer’s case and locate the wires bringing power to the terminals of the PSU. Check each wire, both going in and coming out, to ensure they are correctly seated.

If there is any connector, like the XT60 connector, between the power outlet and the power supply, check it also. For example, this user found out his power supply wasn’t working because of a burnt XT60 connector.

Next, if your printer’s wires are held in place on the terminals by screws and tinned solder, you might want to change this. During the printer’s operation, the power supply can overheat and melt the compressed solder, leading to a loose or partial connection.

So, replacing the solder with something stronger is the better option. In this case, the stronger solution is ferrules. Ferrules provide a tighter connection to the power supply’s terminal and will not melt during operation.

You can get the Ferrule Crimping Kit from Amazon. It comes with 1800 ferrules and an adjustable crimper that you can use for both thin and thick wires.

The crimper has an insulated, ergonomic handle that makes it quite easy to use. Also, the ferrules are made of high-quality nylon insulation sleeves and copper tips for connecting to the terminals.

Once you get them, install them on the tips of all your wiring cables and connect them to your power supply. Do this for the wires going in and coming out of your printer’s power supply for the best result.

You can follow this video to learn how to install Ferrules on your printer.

6. Ensure the Wires are Connected to The Right Terminals

Ensure all your wires are connected to the right terminals, as this can be what’s causing problems in your PSU. This fault is commonly seen in cheap printers and DIY printers.

Here, people assembling the printers mistakenly connect the ends of the power cable to the wrong terminals. For example, they can connect the ground wire to the positive terminal and the positive wire to the negative terminal.

One user made that same mistake, resulting in his machine not lighting up. Their positive red wire was connected to the negative terminal(V-) and the black negative wire was connected to the positive terminal(V+).

If the wiring configuration is messed up like this, the power supply won’t work. So, trace the wires from the power cable and make sure they are all at the right terminals.

The red positive wire should go to the positive terminal, the black negative wire should go to the negative terminal, and the green/yellow ground wire should go to the ground terminals.

7. Check and Replace the Fuse If It Is Burnt

The fuse protects the parts of the printer from damage from power surges. You might have a blown fuse if your printer’s power supply isn’t working.

A common cause of this is when one of the printer’s parts tries to draw more power than what the printer is capable of. The fuse blows up to protect the printer from the power surge.

Most printers have their fuses in a spot just above the plug and switches of their printer. Remove the fuse cover and check it to ensure the wire inside is intact. Check for any char or burn marks around the fuse.

You can also test the fuse by checking for continuity with a multimeter. I recommend using the versatile AstroAI Multimeter from Amazon.

You can check the fuse for continuity using the same methods I outlined above for testing the power cable.

If you spot any irregularity around the fuse, you must replace it. Check the current rating of the fuse you’re replacing, then replace it with one rated for the same current.

8. Check the Power Supply’s Internal Components

As a last resort, you can open up your PSU to check its internal components to see if you can detect and replace any faulty parts on its board. You should only try this fix if you have some experience with soldering and electronics.

The power supply is very dangerous and opening it without taking the required precautions can lead to electrocution.

Here’s how you can open up your PSU:

• First, place a multimeter across the output terminals of your PSU. If you’re not reading 12V or 24V, there might be a problem inside your PSU.
• Disconnect your PSU from all power sources and remove it from the printer’s case.
• Using a screwdriver, remove the screws from the PSU’s case to open it up. Be careful not to touch any of the board’s components.
• Remove the PSU’s board from the case without touching any of its components.

THE LAST STEP IS VERY IMPORTANT BECAUSE THE CAPACITORS ON THE BOARD RETAIN POWER CHARGES WHICH CAN ELECTROCUTE YOU. SO, YOU NEED TO DISCHARGE THE CAPACITORS BEFORE WORKING ON THE BOARD.

• To discharge the capacitors, take a screwdriver with an insulated handle and place them across the capacitor’s terminals on the bottom of the board. Hold it there for a while to get rid of any remaining charge.
• Next, check the board’s components for any damage. This can be burnt or charred surfaces, burning smells, partial contact with the board, etc.
• Components that often get damaged include: NTC inrush current limiter thermistors, capacitors, MOSFET transistors, etc.
• If you discover any damaged components, remove them, and solder a new one to the board. Make sure you find the exact model to replace the old part.
• Once you’re done, close up the PSU, re-attach it to your printer, and attempt to turn it on again.

This great video from Thomas Sanladerer shows how to open and fix standard PSUs.

9. Replace the PSU

If you’ve tried all these steps and your PSU still isn’t working, you will need to replace it. The prices of PSUs have fallen lately, so you can get a good quality brand without breaking the bank.

However, before you get a new one, you should conduct a post-mortem on your old PSU to ensure the same thing doesn’t happen to the new one. For example, how much power do the bed and the hot end draw? What’s their voltage rating? Can the new PSU provide that power? Are there any shorts in your printer?

Once you’ve got all this information, you can ask for recommendations on the brand of PSU you should be buying. A High-quality brand you should look out for is Meanwell. Their power supplies come well recommended with a lot of good reviews.

You can get this 24V, 350W Meanwell LRS-350-24 PSU from Amazon. It is perfect for small and medium format printers like the Ender 3.

In fact, both Ender 3-S1 and Ender 5 users have reviewed it positively saying that power cuts and interruptions stopped once they swapped to the Meanwell PSU. However, you should know that users have complained about the fans being a little too loud.

Here’s a video on how you can properly replace a burnt-out PSU.

A faulty Power supply can seem challenging to troubleshoot for beginners, but trust me, it’s not that hard. Just follow the tips I’ve provided in the guide, and you should be able to quickly get your printer working again!

Good luck and happy printing!