I think I fried my Arduino Mega 2560 R3

I wanted to externally power my Arduino. The specs on my external PSU showed 18V DC output. On the limit, but should be ok. I connected it to my Arduino. Found out that this killed my Arduino. After measuring the PSU, I measure 24V DC!!! So something wrong with that PSU for sure.

If I now connect my Arduino with my PC, it has issues with USB. Device Manager says "Unknown USB Device (Device Descriptor Request Failed)". Although, the Power on LED is on, and I see the on board LED flashing twice. So I guess at least something is still working. Maybe it just corrupted the boatloader? Can that be?

Anyway, any experts here on this forum with some ideas? Can I do some checks, or measure something on it, to identify the issue? Would be nice to recover from this 50 EUR disaster :slight_smile:

(PS. I already ordered a new one - this time a cheap clone or less than half of the price - just want to see if they are as good as this one).

Original or clones will both fail if the power rails are abused.

The prefered voltage to supply to the barrel jack is 7 to 10 volts regardless of clone or original.
That voltage range will give you an extended life for the board. (excluding 3.3 V based boards)

It is easy enough to try and burn a new bootloader (search arduino as icp or icsp)
If it works (doubtful) then you were indeed lucky.

There is also a loopback test you could try (see the sticky post for that)

If not then consign it to the bin with lessons learned.

Thanks for the advice :slight_smile: For all clarity, of course that the clone won't be more resistant to exceeding power. I just meant that I was curious to buy a cheaper version, and see if it works as good as the original.

I also doubt that the bootloader is the issue. That's why I asked if some people have experienced overpowering, and how destructive that is. Maybe it's only a matter of replacing a simple component like the power regulator, but I have no experience with it.

Not sure what you mean with "loopback test" - let me figure that out first.

Just tried the loopback test - which failed obviously. For the loopback test to work, I first need to be able to find my Arduino on a port on my computer, which isn't the case.

The voltage regulator is the most likely thing to have failed, but may not be the only thing. If you are good at soldering surface mount parts, it might be possible to replace it. I think I would do the research to find what regulator I would need, and order one next time I need to do a Digikey order. Meanwhile, just put the dead Mega in your junque box. You would need the schematic for the R3 to see what regulator they used.

ShermanP:
You would need the schematic for the R3 to see what regulator they used.

You make it sound like the schematic would be hard to find:

To the OP: Depending on what type of power supply you are using, it is not unusual for the voltage to be rather high with little to no load. This is particularly true for the basic wall-wart type supplies intended for some specific piece of equipment where the load was known, they are often little more than a transformer, capacitor, and a few diodes, with no regulation at all.

It would be worth a try at this point to remove the regulator and see if the board will run off of USB power.

Many clones may use different regulators with different specs so if you try to replace it make sure that you use a comparable specification brand.