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Author Topic: Exploded diode(?) need info in replacement part  (Read 1368 times)
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Hi,

I had a slight setback with my Arduino Mega 3. Something (I believe a diode) exploded off the front. Attached is a picture of the part that popped. I'm hoping that I can just order whatever it is and solder in a replacement. In the attached photo the bad part is in the lower left, does anyone know what it is and where I can acquire a replacement?

Thanks!


* photo.JPG (437.58 KB, 1296x968 - viewed 62 times.)
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I've heard of a Arduino Mega and Arduino Mega 2560, but not a Arduino Mega 3? Do you have a link to your "Mega 3" board?

The component that blew up is a capacitor, most likely the same value as the one to the right of it. It most likely blew up because of supplying too high a voltage via the external power connector or Vin pin.

Lefty

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Sorry Mega 3 might be the wrong name for it. I know there are multiple versions of the Mega board and mine says MEGA03 on the back. I saw it referenced online as Mega 3 somewhere but I'm not sure of the exact model.

I've searched for the numbers on the capacitor and I'm not having a lot of luck finding something that matches. I'm pretty new to surface mount components so I'm not sure where to look. Any advice on where to find a swapable part?

The Mega on the arduino.cc hardware page looks very different from mine in that area of the board.
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Well where did you buy it? There must be a link to your board somewhere?

Lefty
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Looks like this is what you have.
The Arduino Mega boards used to use orange/yellow SMD capacitors - perhaps they changed this in some batches or your board is a clone version.
Anyway - yes it is a capacitor that has blown - of value of 100uF I think.

Places like digikey/farnell etc can be daunting places to visit but somewhere like that is the best place to start to look for one.

I suggest you try to work our exactly what you did to it as well - then you can make sure you don't do it again...
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Thanks for all the helpful responses. I spoke to the vendor I got my Arduino from and they blamed a mismanufactured  shield that was plugged in. Both are being replaced for free so I can end my resistor scavenger hunt.

Thanks again.
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Well that's good news smiley
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It looks like the surviving capacitor is rated at 16V.  If the input capacitor was also rated at 16v then overvoltage was most likely the problem.

Don
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Glad you are getting the board replaced.

Having just learned this myself, you may have done nothing wrong.  The caps on that part of the board are Tantalum.  An interesting property of Tantalum (depending on the dielectric) tend to ignite (explode) on failure.  During the solder process, it is possible for the heat to have weakened the dielectric, causing an internal short.  The capacitor was unable to self-heal itself and went "pop!"
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Actually tantalum and electrolytic capacitors can be quite dangerous when over-voltaged. I have seen small electrolytic capacitors explode like a shotgun shell ejecting shrapnel that could easily destroy an eye for quite a distance.

I always use capacitors rated for at least 2.5x the maximum anticipated voltage to be applied.



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Quote
I have seen small electrolytic capacitors explode like a shotgun shell ejecting shrapnel that could easily destroy an eye for quite a distance.
I did this... Thankfully didn't destroy my eye.
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