Arduino Nano V3.0 is not responding and is acting weird.... possibly fried.

Please help!

I was working with my Arduino Nano V3.0 (Funduino not Gravitech... :0) and everything was fine. I changed a few wires on my breadboard and then the next time I plugged in the PC's USB cable into the Nano, the Nano wasn't detected. No sound from Windows XP fo USB device plug in notification.

The board still seems to function in a weird way though. I noticed that with USB power, the blue power LED on the nano is lit but much dimmer than normal. And also, the TX and RX LEDs are flashing simultaneously and at a dim level also. Reset doesn't fix the problem.

I tried powering the Nano with a 9volt battery only and the power LED lights up at full brightness, the TX and RX LEDs are inactive, but my last loaded sketch doesn't work.

I tried searching the internet for answers but there's no clear solution since I can't figure out if I did something wrong or if the board simply failed. Any replies to this is much appreciated.

-G

I changed a few wires on my breadboard and then the next time I plugged in the PC's USB cable into the Nano, the Nano wasn't detected.

More specifically? What did you change?

Perhaps you zapped it. They don't normally fail for no reason.

Well first off, I'm not grounded so I could have zapped it.

But the change I made was I added a 50k pot to the breadboard. I wired the pot to Analog input 1 and supplied 5v power and ground. Then, after I plugged in the USB is when it started acting weird. Also, note that I have a hall sensor wired in a similar fashion and is routed to A0. Before the pot was added, the hall sensor setup was working fine. These two are sharing the 5v and now I'm wondering if that is the issue.

Thanks for the reply.

Hi G, I have the same problem with a nano - got it working again (for a few days now) by supplying 5v to the 5v on the nano while connecting USB.

cant say if it will work for you but it does for me - if i disconnect external 5v the usb link dies.... So i guess i (and maybe you) have fried the 5v passthrough in the USB chip on the nano :blush:

-S

ooopss! Wow you nailed it! That solved my problem. Weird. So the 5v passthrough in the USB chip is dead then. So connecting up 5v to the VIN terminal is where I'm connecting the power at but device recognition is not consistent every time I disconnect and reconnect. I suppose I can just leave it connected all the time.

I have a couple questions now. 1) Does it matter if I connect the power to VIN or 5V? I'm using a +5V power supply rated at 3A. When I connect to either VIN or 5V, the blue power LED lights up. 2) Is it safe to use a 12V source or 9V source (ie typical 9V battery) for VIN? I was using a 9V battery to demo my circuits when I had to transport my breadboard away from my power supply. My understanding is that the Nano is smart enough to detect the incoming voltage (up to 12V) and compensate for that. 3) So what could have fried the 5V passthrough?

Thanks for the help!

g_von:
ooopss! Wow you nailed it! That solved my problem. Weird. So the 5v passthrough in the USB chip is dead then.
So connecting up 5v to the VIN terminal is where I’m connecting the power at but device recognition is not consistent every time I disconnect and reconnect. I suppose I can just leave it connected all the time.

I have a couple questions now.

  1. Does it matter if I connect the power to VIN or 5V? I’m using a +5V power supply rated at 3A. When I connect to either VIN or 5V, the blue power LED lights up.
  2. Is it safe to use a 12V source or 9V source (ie typical 9V battery) for VIN? I was using a 9V battery to demo my circuits when I had to transport my breadboard away from my power supply. My understanding is that the Nano is smart enough to detect the incoming voltage (up to 12V) and compensate for that.
  3. So what could have fried the 5V passthrough?

Thanks for the help!

  1. Applying 5 volts to Vin is too low a voltage for the on-board +5 vdc voltage regulator to operate correctly, it should be in the range of 7 to 12 vdc or so. Applying +5vdc to the 5V pin will work as you are then bypassing the on-board voltage regulator to power all the stuff on the module directly from your external regulated +5vdc power supply.

  2. Yes it is safe, it’s not about being smart it’s the fact that the Vin voltage only goes one place, to the input of the on-board +5vdc voltage regulator which will then power all the stuff on the module.

  3. If the board will not work on USB only power and you have tried more then one USB connector on your PC then you most likely have a bad (open) diode (D1) on your module and replacing it should correct the situation.

Lefty

retrolefty:

  1. Applying 5 volts to Vin is too low a voltage for the on-board +5 vdc voltage regulator to operate correctly, it should be in the range of 7 to 12 vdc or so. Applying +5vdc to the 5V pin will work as you are then bypassing the on-board voltage regulator to power all the stuff on the module directly from your external regulated +5vdc power supply.

  2. Yes it is safe, it’s not about being smart it’s the fact that the Vin voltage only goes one place, to the input of the on-board +5vdc voltage regulator which will then power all the stuff on the module.

  3. If the board will not work on USB only power and you have tried more then one USB connector on your PC then you most likely have a bad (open) diode (D1) on your module and replacing it should correct the situation.

Lefty

Thanks Lefty,

  1. What you say makes sense but when I connect the board to the 12V(1A) source Windows XP never recognizes the device. When I go back to the 5V(3A) connection, wXP then recognizes it.

  2. Ahhh okay. I learned something new today!

  3. Yes, I tried more than one USB port. And actually, it makes sense that I killed the diode because before the blue power LED was very weak when only connected to USB. Now, it doesn’t light up at all! So looking at the schematic here:
    http://arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf
    I think I have to replace part MBR0520. Digi-key has so many versions of this part:
    http://www.digikey.com/scripts/dksearch/dksus.dll?vendor=0&keywords=MBR0520
    How do I know which one to choose?

Is this(see attachment) the part,D1, on the bottom of the board(highlighted in RED) that I have to replace?

g_von:

retrolefty: 1. Applying 5 volts to Vin is too low a voltage for the on-board +5 vdc voltage regulator to operate correctly, it should be in the range of 7 to 12 vdc or so. Applying +5vdc to the 5V pin will work as you are then bypassing the on-board voltage regulator to power all the stuff on the module directly from your external regulated +5vdc power supply.

  1. Yes it is safe, it's not about being smart it's the fact that the Vin voltage only goes one place, to the input of the on-board +5vdc voltage regulator which will then power all the stuff on the module.

  2. If the board will not work on USB only power and you have tried more then one USB connector on your PC then you most likely have a bad (open) diode (D1) on your module and replacing it should correct the situation.

Lefty

Thanks Lefty,

  1. What you say makes sense but when I connect the board to the 12V(1A) source Windows XP never recognizes the device. When I go back to the 5V(3A) connection, wXP then recognizes it.

That would imply that you have a defective on-board +5vdc voltage regulator in addition to the bad diode.

  1. Ahhh okay. I learned something new today!

We all do if we are lucky.

  1. Yes, I tried more than one USB port. And actually, it makes sense that I killed the diode because before the blue power LED was very weak when only connected to USB. Now, it doesn't light up at all! So looking at the schematic here: http://arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf I think I have to replace part MBR0520. Digi-key has so many versions of this part: http://www.digikey.com/scripts/dksearch/dksus.dll?vendor=0&keywords=MBR0520 How do I know which one to choose?

Well unless you want to buy minimum quantity of 3,000 I would suggest you just buy one of the second listed one.

Is this(see attachment) the part,D1, on the bottom of the board(highlighted in RED) that I have to replace?

Yes. Lefty

retrolefty: That would imply that you have a defective on-board +5vdc voltage regulator in addition to the bad diode.

So at this point, I have to buy a replacement regulator and diode. With the cost of the new parts and shipping and time/work to fix the board, I might as well get a new board...

Well unless you want to buy minimum quantity of 3,000 I would suggest you just buy one of the second listed one. Thanks.