Removed Arduino Uno Polyfuse

About: Welder by trade, trying to start business and tinkering for fun.

I am working on a project that needs the Arduino to only work if the power supply is connected and not if only USB is connected. So a quick search told me to remove the polyfuse from the board which I did without researching any further.

When I tried to connect the Arduino to the pc it wouldn't connect and a further search (which I should have done before going ahead and desoldering the fuse) told me that the fuse is needed to connect.

A little prodding about on the board told me that all was not lost (removing the fuse had destroyed it) and if I supplied the 5V the pc gave a pleasant noise that said "there it is".

Luckily there is 5v really close to where the now deceased fuse used to be (the regulator) so a simple bit of wire solved the issue and now its working exactly the way I wanted it to with the possible exception of I may have wanted to upload new code without the power supply attached but this is an acceptable work around.

Please excuse the ropey soldering but the arduino is in place and would have took a lot of work to get it out to make a neat job.

Step 1: Simple Connection to 5V.

Thats it just connect the tab of the regulator to the pad that the fuse is usually soldered to.



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    8 Discussions


    Question 9 days ago

    When you removed the polyfuse you seem to have damaged its connection . So now you have repaired the connection with a solid wire and it works as it should have if you had been more careful

    4 more answers

    Answer 9 days ago

    Its a possibility but I have looked with a magnifying glass and cant see any damage but my old eyes are not what they used to be so I wont disregard that especially as the operation was carried out with limited access.


    Reply 8 days ago

    Yes I know the experience with the eyes. I tried to find a circuit for that uno board but everything has changed now so much I just got lost. If you happen to have cataracts get them done .Three grand an eye here but what a difference. Post a circuit if you find one .


    Reply 4 days ago

    Thanks for that . very informative . The rugged duino page particularly so.


    6 days ago

    Interesting to know, thanks for sharing!


    Question 9 days ago on Step 1

    What did you use to bridge the connection? >14ga copper is what it looks like

    1 more answer

    Answer 8 days ago

    It's about 0.6mm ish copper wire.