How to Fix Fried Arduino Nano/Uno/Mega




About: Hi, I'm Nemeen, Electronics Enthusiast! I have seen a huge decline in electronics hobbyist in past few years. I started this channel in order to inspire you to create. Hopefully, you will find something tha...

While I was working on a project which includes an arduino I accidentally shorted it and now its dead. But it can be fixed really easily, So lets get started !

In this post I am fixing the Arduino nano if you have fried Uno or mega skip to step 7, but do read all steps once.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Watch the Video

If you get bored of reading stuff you can watch my videos on YouTube ! Click Here

Step 2: Analyzing the Problem !

There are two ways in which you can burn your arduino

1) USB

2) External Vin pin

Step 3: USB

If you were using USB to power your arduino when it died if you flip it around you will see a black component, which is a diode and if u look closely it has a small bulge area or a spot swelled indicating it is dead which is the case for me so replacing it will fix the arduino, but before fixing it lets look at the other way you might have shorted it.

Step 4: Vin Pin

If you were using Vin pin when it died then if you flip it around you will see a small bulge area on this which is a voltage regulator replacing this will fix your issue, but in my case it works via Vin pin but not USB so I need to replace the diode so let's do it

Step 5: Components & Tools!

1) Soldering Iron

2)SMD MBR0520Tp Schottky Diode

3)AMS1117 5V

Step 6: Soldering !

I don't have SMD Schottky Diode at the movement so I will be using general purpose short key diode.

And its time for the Soldering

I have turned the legs of diode for my convenience.

and Its done !

Step 7: For Uno and Mega

Similarly if you have shorted your Arduino Uno or Mega, You need to replace 500mA Fuse(Shown in pic 2) or Voltage regulator(Shown in pic 3) which is same as nano

It will fix the issue !

Step 8: Thank You !

If you like my work

Feel free to check out my YouTube channel for more awesome stuff:

You can also follow me on Facebook, Twitter etc for upcoming projects

1 Person Made This Project!


  • Made with Math Contest

    Made with Math Contest
  • Multi-Discipline Contest

    Multi-Discipline Contest
  • Robotics Contest

    Robotics Contest

15 Discussions


1 year ago

This is excellent. Thanks a bunch! I fried the diode by accidentally putting 14volts through the Vin. I was able to do a quick fix by replacing the surface mount with a through-hole as you showed. Literally I was back to work in 30 minutes and "I learned something today." :D I'll try not to fry more boards down the road. But if I do I'll be able to fix them.


1 year ago

Has anyone run into bad crystals on the Uno? Seems to be more common on "cheap" units, I had it happen before but evidently the real cause might have been a dodgy USB-serial chip. Alas its hard to change those, it can be done with a rework station but its a complete horse. Symptoms: TX/RX lights not working, yet everything else does and if you swap socketed chip into working unit all is then well, it will run code fine just not update.

1 reply

1 year ago

Good to know! =D


1 year ago

Very clear instructable, thanks for sharing the information...


1 year ago

I recently fixed an Arduino Mega because of a blown voltage regulator (a few months ago). Thanks for putting up such a clear Instructable and video for others who may find themselves in the same situation. I hate seeing good stuff thrown away because people don't take the time to figure out what might be wrong.

Great job.


1 year ago

Isn't the fuse on the Uno at least, resettable?

Datasheet gives it as good to 100-A, trip at 1-A typical. Normally, just letting it cool is enough.

In my experience, the diode is the most likely component to burn out. Beware confusing Vin and 5-V out if connecting a supply other than though the 2.1-mm socket

2 replies

Reply 1 year ago

Some Uno's (or other Arduino's, for that matter) have a type of fuse called a PPTC fuse. It is just a resistor, that, when it heats up, increases resistance exponentially. As it cools, the resistance lowers. So, technically, when the PPTC "fuse" trips, there is actually a small current passing through.

It just depends on the manufacturer whether they put that type of fuse on or not.


Reply 1 year ago

Yes, you're right. The spec is hold at 500-mA, but as Bourns describe as "trip" at 1000-mA. The point is there is no need to replace unless you whack 100-A through the Uno. It's probably a bit more sophisticated than a PTC resistor, with a defined "knee". A cursory look at the schematic suggests that it only protects the USB supply, by which time you've probably crashed the PC.


1 year ago

Thank you for this post. A quick easy fix for diode replacement on Nano - Thank you.


1 year ago

Nice Video. Seems like a fairly easy fix and cheaper than replacing a board. Thakns.


1 year ago

I will investigate this method to repair an ethernet card fryed by a bolt.


1 year ago

I've got a couple of Mega's sitting around that are dead. This is a cheap way to see if I can get them going again. Thanks!