Arduino uno 3.3v capacitor burned out

[charlesli]

I accidentally hooked up the Arduino to a 12v power supply while using the Arduino Uno to connect to my screens and power them up, which made my board burn up in a heartbeat. I think maybe the 3.3v capacitor is burnt out, how should I repair it?
My board is normally connected to the computer using USB and the screen is powered by 12v.

 

[Wp100]

Hi,

Repairing SMD boards and getting the right componets can be difficult plus you have no idea what other parts may be blown or partially damaged that will later cause early failure.

As you can buy decent clone Uno boards for so little, would just bin this one.

 

[schmitt trigger]

I second wp100’s suggestion.
There will be plenty of damaged devices.

 

[charlesli]

Hi,

Repairing SMD boards and getting the right componets can be difficult plus you have no idea what other parts may be blown or partially damaged that will later cause early failure.

As you can buy decent clone Uno boards for so little, would just bin this one.

So your suggestion is that I would be better to replace a board?

 

[Nigel Goodwin]

So your suggestion is that I would be better to replace a board?

They cost so little, you may as well order a few boards - as you thought the visibly blown device was a capacitor (it's not, and looks nothing like one), it's probably as well you don't try replacing SM components.

 

[gophert]

The blown part is a voltage regulator with two of the four pins connected to ground.
I disagree with the others. Now is the perfect time to practice soldering SMD parts. If you assume it is damaged beyond repair, you can only be happy if you fix it and, even if you don't fix it because other parts are tanked, you'll still get a chance to rework an SMD board.
The voltage regulator probably died first and may have tried its best to protect the rest of the board until its failure. So, there is a chance. A 3.3v, regulator ina four-pin package. That doesn't look like a genuine Arduino board - is it a clone?

 

[charlesli]

The blown part is a voltage regulator with two of the four pins connected to ground.
I disagree with the others. Now is the perfect time to practice soldering SMD parts. If you assume it is damaged beyond repair, you can only be happy if you fix it and, even if you don't fix it because other parts are tanked, you'll still get a chance to rework an SMD board.
The voltage regulator probably died first and may have tried its best to protect the rest of the board until its failure. So, there is a chance. A 3.3v, regulator ina four-pin package. That doesn't look like a genuine Arduino board - is it a clone?

Thank you very much for your reply, I think you have a good point, my board is Arduino UNO R3, do I need to buy a 3.3v regulator in a four-pin package and solder it on?
I would try to fix it first, and if it doesn't work well, I would consider replacing a board.

 

[gophert]

The part is $0.60 and shipping will be 10x that.

https://www.mouser.com/ProductDetail/Texas-Instruments/LP2985-30DBVR?qs=iSMark9AYDWJqjjCQuouOw%3D%3D&gclid=Cj0KCQjw3f6HBhDHARIsAD_i3D_E32sX5WNL4ne8GPGzPuXdVwCdOMzdEqrmMJ5f1KEoaKUnwmHR8IgaAqQZEALw_wcB

An Arduino Uno R3 can be ordered with the same shipping cost for $27 more.

https://www.mouser.com/ProductDetail/SparkFun/DEV-11224?qs=WyAARYrbSnZVy5ZI7%252B2ULg%3D%3D

shipping in the US is about $7. I don't know what pains you'll have getting anything into Australia.

 

[Pommie]

If you remove the burnt part and power it via USB then you'll know if more of the circuit is damaged. A.F.A.I.A., nothing on the board needs the 3.3V supply yo work.

Mike.

 

[charlesli]

If you remove the burnt part and power it via USB then you'll know if more of the circuit is damaged. A.F.A.I.A., nothing on the board needs the 3.3V supply yo work.

Mike.

Everything is working fine for me through the USB power supply, and I can use the Arduino board normally.