A little backstory to help you understand the situation. I put the 3D printer together and turned it on and everything seemed fine until I started printing. It didn't even get the first layer down when the screen reset and so did the print. I didn't think anything of it, I just went back and tried again, but this time right when I pressed start, the fuse blew.

I have done some research on the issue and haven't had any luck besides recommendations for putting in a secondary fuse before the power supply (which I will be doing in the near future). As for now though, my plan is to just replace the power supply fuse if possible. I went to the hardware store and picked up a Bussmann T5AL/250V fuse (photo attached below) and before I put it in, I just want to make sure this is the correct fuse and I'm not going to kill the entire printer this time.

Picture showing the internals of the power supply unit:

PSU, cover removed showing fuse

Picture of the fuse I bought:

Picture of the fuse I bought

Any and all help is very much appreciated because as you might expect, I'm not too happy with the printer so far.

  • $\begingroup$ use caution when soldering leads to the fuse that you do not de-solder the internal fuse from the caps. $\endgroup$
    – fred_dot_u
    Jul 6, 2018 at 1:39
  • $\begingroup$ Hi Kyle, welcome to 3D Printing.SE! My first printer was also the Anet A8. Although not the best printer around you can make the printer a lot better than standard out of the box. Mine is doing very great prints now. As a caution, be very careful when tinkering with the power supply! Please let us know why you think the fuse blew. Is there any action you know of that may have triggered this? Short circuit, power peak, etc. $\endgroup$
    – 0scar
    Jul 6, 2018 at 7:00
  • 2
    $\begingroup$ If you are not 100% confident of what you're doing, you have no business messing with the internals of a power supply. You should buy a new power supply. $\endgroup$ Jul 6, 2018 at 7:15

2 Answers 2


The fuse rating is same as described on the board - so that shall be no issue with it.

My main concern is why the fuse is down?

Was there a short-circuit? As this is mains fuse - that suggest a big-bang, so, please check carefully hot-end and bed heater connections before restarting the device, to avoid replacing another fuse.

  • 1
    $\begingroup$ Especially check the leads to the bed heater and the solder joints on it. Find a way to provide strain relief to the wires so the flexing doesn't take place at the solder point. Make sure your hot end wires are insulated at their solder joints too. $\endgroup$ Jul 7, 2018 at 21:38

To add to the answer of @profesor79 (which you absolutely need to address first (find the cause why it blew); else the fuse might blow again), you might be interested in installing fuse clamps. As @fred_dot_u mentions:

use caution when soldering leads to the fuse that you do not de-solder the internal fuse from the caps

is that if you incorrectly solder the fuse, you might de-solder the caps, soldering the clamps is easier.

Example of fuse clamp:
5 mm fuse clamp

  • $\begingroup$ as long as there is a place on the board and drilling holes for pins will not cut other paths the board. $\endgroup$
    – profesor79
    Jul 6, 2018 at 9:58
  • $\begingroup$ @profesor79 I would just cut off one leg and insert in the existing hole, no drilling necessary. Anyway, what I actually would do is buy a new supply (if I'm unsure about the reason why it blew). $\endgroup$
    – 0scar
    Jul 6, 2018 at 14:31

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