So I got my new Uno R3 and the first thing I did was trying to burn a bootloader onto the Nano.
“Hi, my name is Uno and I’m from Italy. Nice to meet you.” says the Uno. I like to think that electronic items have personalities. Lol.
Back to the burning the bootloader. I followed the schematics on the arduino.cc website and here is how to set it up.
So I fired up the Arduino IDE and it failed again. Done all sorts of tinkering and couldn’t get it to work. At this point, I assumed that the Nano is a goner. So, I played around with the Uno for some time and chucked the Nano back in its’ box.
Today I had some free time so I took it out again and decided to check every single connection on the Nano’s PCB by referring to the official schematics.
This was extremely tedious as all the components on the Nano are SMDs (Surface Mounted Device) and the pins are notoriously small. It made my multimeter’s fine tip probes looked like they’re giants.
I soldiered on and all was well until I reached pin 29 of the ATmega 328 (there are 32 pins in total!). That is the RESET pin and when I used the continuity test, it detected that the RESET pin is shorted to ground all the time. No, it shouldn’t do that, it should be pulled high. So I looked around to find any soldering faults that made the RESET pin shorted to ground (praying to God that it’s not a PCB design fault).
Lo and behold, I found this. On the left side of the Nano, there was a tiny solder joint between the GND and RESET pin. This was causing the chip to be on RESET all the time. The below picture is after I fixed the solder joint.
I removed it easily by using a pen knife and you can see the leftover in the picture above. That is some poor soldering by the folks in Hong Kong (I suspect China but Hong Kong is China, so yeah China lol). Testing the pins again and I no longer find that the RESET pin is shorted to ground. Hopefully this is it.
Connected it to USB and immediately the ‘L’ led lit up and blinked, that’s a good sign. So I uploaded the blink sketch and it was successful. Praise the Lord 🙂
This has been a frustrating journey in the world of Arduinos. I regretted buying it from Ebay just because it was cheap. I spent so much time tinkering with it and there was once I mistakenly shorted 5V with Ground and a diode blew. I had to remove it and solder a jumper wire between the two pads.
It’s not pretty but at least it works. Now I should be more careful not to do anything silly.
But in the end, it was a happy ending and the Nano came back to life. To commemorate the revival of the Nano, I’ve done this.
The moral of the story : Don’t get anything that’s ‘too good to be true’ on Ebay. It usually doesn’t end well.
Long live the Nano!