Arduino Nano 33 BLE Sense won't turn on anymore

[mc_mc]

Hello!

This is my first post, I read the guidance and hope not to mess up. But I accept tips on making better posts. Also, English is not my first language, so please be patient

I was making some tests with my new Arduino Nano 33 BLE Sense and ran into some trouble. I was trying to make a circuit to power an analog non-addressable RGB LED strip that works with 12V.
I've adapted the instructions from here: https://learn.adafruit.com/rgb-led-strips/usage
As this version of the arduino board only provides 3.3V on its outputs, I used a logic level converter (https://learn.sparkfun.com/tutorials/retired---using-the-logic-level-converter). I programmed the digital output to high and it worked by powering it either from the USB or the Vin. I've attached the circuit I made at Fritzing.

After just putting HIGH to the output, I wanted to PWM it. So I got a simple code for that and put the code to load. It can take a while on my computer, so I got distracted by other activities. When I returned to the Arduino software, I noticed that it failed to load the code because the Arduino disconected. I checked the board and the RGB LED was fully red and the Nina module was super hot. At this moment, I realize that I was powering the Arduino board trough both USB and Vin at same time. I've read around that it is not supposed to be an issue, but I think it is important to mention. Now when I try to power the board (either from USB or Vin) it only lights the RGB LED red and start heating the Nina module.
This is the code I tried to load:

Code: [Select]


int ledPin = 11;
float sinVal;
int ledVal;

void setup()
{
  pinMode(ledPin, OUTPUT);
}

void loop()
{
  for (int x = 0; x < 180; x++)
  {
    // converte graus para radianos e então obtém o valor do seno
    sinVal = (sin(x * (3.1412 / 180)));
    ledVal = int(sinVal * 255);
    analogWrite(ledPin, ledVal);
    delay(25);
  }
}


So, after reading some posts here in the forum where people mention burned diodes, I decided to measure the components and I believe I found 4 capacitors and 1 resistor short-circuited. I checked the schematics, but I cannot identify which ones are the burned components. I circuled the components in the image below. I also attached the schematics.

Is this really the problem? Could someone help me to identify the value of these components? What have caused this on first place?

Any help is appeciated, thank you!

[Klaus_K]

Welcome to the forum

Getting distracted when you have high voltage sources near your 3.3V only Arduino is a bad habit. Be happy you are not a heart surgeon. Otherwise it would not just be a dead electronic circuit on your table. We all payed our prices for learning this lesson.

I recommend to draw a real schematic next time (hand drawn on paper is OK). Fritzings are not schematics. Schematics are the language of electronic circuits. Its precise and established. Reading Fritzings is often like reading finger paintings. It looks beautiful to the eye but does not have all required information in it.

What is your goal? Do you want to move on or try to repair the Arduino? I am not sure I would try. I would get a new one and be more careful next time. The module getting hot is not a good sign. If it is damaged internally you cannot do anything.

[mc_mc]

Hi Klaus_K! Thank you for your reply


Yes, I would not be a good surgeon

But I don't think that if I was supervisioning the circuit it would behave differently.


This is such a simple circuit I didn't think about drawing a schematic for it (yet I blew the Arduino with it, I can see the irony). I only used fritzing because it's practical and illustrative, making it easy to show here what I've being up to. But you are right, I should have drawn the schematic.

About what to do next, I'd like to try to fix it because this board is not commercialy available in my country. I had to import it, wich is not a huge problem but is not ideal (high costs, time consuming, etc). The components are way more accessable for me right now. I know there's still a big chance that the board won't work afterwards anyway, but I think it's worth the shot! So, it would be nice if you or someone else could help me to figure out the values of the components
 

[Klaus_K]

OK, here is what you can do.

Download the schematic and EAGLES from the Arduino store. Under DOCUMENTATION.

https://store.arduino.cc/arduino-nano-33-ble

Go to the following site and Drag & Drop the NANO33BLE_V2.0.brd (from the zip file) into the viewer.

https://www.altium.com/viewer/

You can now click on the pads and should get the name on the right side. Compare with the schematic.

e.g., your blue box, lower right corner on the brd file, pad name C9-1 and C9-2, schematic says it is a 100nF

[mc_mc]

Thank you! I'll try that. Unfortunately I'll have to wait 2 weeks due to the Holidays. But I'll be back as soon as possible with the follow up!

Happy Holidays!