Arduino Nano Every doen't work without USB connection

[Lucky-Luka]

Hi all
I've tried my first Nano every project after several Arduino UNO projects.
I power the NANO and the circuit using a 9V 1A wall wart and the PC usb cable.
In this configuration everything works just fine.
After I've programmed the NANO I've tried to remove the USB cable and the power led on the board turns off.
2 GND pins are connected.
Vin pin is powered by 9V
The rest of the circuit is powered by 5V using a 7805 linear voltage regulator.
I don't know what's going on since it's my first NANO project.
Do I have to connect the 5V pin? I thought it was a power output.
Can anyone help me?

p.s. I've noticed that the circuit is working just fine IF I connect the usb port to a power supply (the PC is not needed:  it's needed usb power... is it normal?)

[james_s]

What voltage do you measure between the Vin pin and ground?

[Lucky-Luka]

9V

[Rick Law]

9V

To debug that further, best if you understand how the Nano gets it's power.

On the USB side, there is a diode between the USB's 5V to the NANO's 5v "bus".  On the Vin side, there is a voltage regulator (and components to support the regulator) between the Vin and the NANO's 5v bus.

Say you USB only, the USB's 5v hit the diode, drops a little (say down to 4.7v) and that powers the 5v bus at a few percent below 5v.

Say now you connect it to a good power supply of say 8v.  That goes through the voltage regulator and (should) regulate down to 5v to power the 5v bus.  If the USB is also connected, it would have been trying to put 4.7v at the bus-end of the diode.  With the bus-end of the diode already at 5v which is > 4.7v, so the diode would block current flowing into the USB cable back to your PC side of things.  The bus has 5v and the NANO is happy.

Say now something is wrong with your Vin side of things and the regulator is NOT putting 5v on the 5v bus.  Say regulator puts out only 1v on the 5v bus.  As you can imagine, 1v isn't going to run your NANO.

------------

(Without USB...)

Now that you've measured the V-in side to be 9 volt, so you know it is putting 9v to your voltage regulator (assuming the PCB isn't damaged thus connection to your voltage regulator is intact), now you measure what the voltage regulator output is - ie:measure what is on your 5v bus.  Pin 27 connects directly to 5v bus.  Measure that and see what the output of the regulator is...

If it is not 5v, replace your 9v supply with another power brick or a NEW 9v primary battery and try again.

[Syntax Error]

I've just tried to find the reference design... nada. Just the pinout. At least Vin is shown as an input.

+edit+ If anyone has the official reference design, please link

It's normal on a classic Nano to directly use the 5V USB bus, with the 5V regulator left 'floating'. A 3V3 regulator *might* be downstream of the internal 5V bus to drive the USB controller. There is a VIN pin, sometimes ambiguously marked RAW on clones, that supplies the 5V regulator when the USB is disconnected. A nominal 9 volts.

Check the 5V regulator is working as I heard on a similar clone, the 5V regulator overheated (100'c+) because the connected computer was driving two amps backwards into the regulator. I understand it's because Vout is higher than Vin, so the output mosfet acts as a dead short between Vout and ground. Please enlighten me if I'm wrong here.

[Lucky-Luka]

Now that you've measured the V-in side to be 9 volt, so you know it is putting 9v to your voltage regulator (assuming the PCB isn't damaged thus connection to your voltage regulator is intact), now you measure what the voltage regulator output is - ie:measure what is on your 5v bus.  Pin 27 connects directly to 5v bus.  Measure that and see what the output of the regulator is...

If it is not 5v, replace your 9v supply with another power brick or a NEW 9v primary battery and try again.

I've changed 9v power supply. Nothing changed. pin 27 (the fourth from the bottom left, right?) gives nothing when USB cable is not connected while it gives 4.5V when USB cable is connected.

In the arduino nano board site i've found "The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source. "

Is this pin 27 power input or power output?
Can I try to connect it to 5V to see if the board works correctly or not?
Thanks

[themadhippy]

Can I try to connect it to 5V to see if the board works correctly or not?

yes

+edit+ If anyone has the official reference design, please link

this  any use
https://www.arduino.cc/en/uploads/Main/Arduino_Nano-Rev3.2-SCH.pdf

[Rick Law]

Now that you've measured the V-in side to be 9 volt, so you know it is putting 9v to your voltage regulator (assuming the PCB isn't damaged thus connection to your voltage regulator is intact), now you measure what the voltage regulator output is - ie:measure what is on your 5v bus.  Pin 27 connects directly to 5v bus.  Measure that and see what the output of the regulator is...

If it is not 5v, replace your 9v supply with another power brick or a NEW 9v primary battery and try again.

I've changed 9v power supply. Nothing changed. pin 27 (the fourth from the bottom left, right?) gives nothing when USB cable is not connected while it gives 4.5V when USB cable is connected.

In the arduino nano board site i've found "The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source. "

Is this pin 27 power input or power output?
Can I try to connect it to 5V to see if the board works correctly or not?
Thanks

As themadhippy already replied above: Yes.  But do make sure that your 5v is exactly 5v and reasonably clean.  You are connecting to the 5v bus directly and intended as output so there is no further protection.  If you over-volt it, your NANO is byebye.

I am almost 100% sure it is going to work since it works off the USB.

I don't want to say the 5v is 4 from the bottom, I don't know your NANO's orientation.  Look at the reply Syntax Error posted a couple of replies back with a drawing attached.  The pinout drawing there has the 5v pointed out clearly and in RED on the lower left of the drawing, and next to the 5V is the RESET.
 Reply with the attachment (drawing of pinout) here:

I've just tried to find the reference design... nada. Just the pinout. At least Vin is shown as an input.
...

(Question 1) With your 9v power supply, how many mA/Amp can it support?
The 4.5v you measured off USB supply is lower than expect, perhaps you are drawing more current than the 9v can put out.

Eitherway, do confirm hooking up 5v directly to the NANO's 5v bus works first, then you can debug where the 9v goes wrong.  To do that, we will have to follow the Vin path to the voltage regulator.

Next step is, with your 9v connected (and without USB connected) use your DMM to measure the voltage on the breadboard, then the Vin pin on the NANO (not where the pin connects to off the board, but on the soldering of the pin to the NANO itself).   So, (question 2), what is the voltage before it hits the NANO and (question 3) what is the voltage of Vin on the NANO board.

We will go from there.  Too lazy to type more now as I suspect it may be soldering of the pin to the board is no good.  The regulator on NANO can fail, but we will go there as needed after Q1, Q2 and Q3 answered.

[obiwanjacobi]

Is the power LED on when you plugin in the 9V?
[2c]

[Lucky-Luka]

Strange things are happening here.
I disconnected the Vin pin. Connecting only the 5V pin from the 7805 stmicro voltage regultator I noticed that the board draw 0.45A! I jumped from the chair. I disconnected every output from it and it still draw 0.45A. It's hot as hell. I first noticed this problem smelling something in the air.. just a little smell of hot plastic... no smoke... touching the 7805 IC I understood something went wrong. I added a dissipator to it. Then I tried to touch the nano. It was super hot.
I disconnected the 5V pin, I connected the usb cable. Still super hot. I don't know if it has always been that hot since I bought it. The board is basically new so I don't know if it's a manufacturing problem.
When the usb is connected Vin = 4.4V
I bought a new one and in a few days it will arrive. This board will be returned.

[Lucky-Luka]

The power led is off when I connect only the vin pin and the 2 grounds. The power led is on when I connect the 5v pin and the 2 grounds but 0.48A is drawn!

[Syntax Error]

Although this article is for the original UNO, it gives an insight into power management in the official Arduino range.

https://www.technobyte.org/arduino-uno-power-supply-arduino-hardware-core/

[Lucky-Luka]

Any guess what happened to my NANO?

[Rick Law]

Strange things are happening here.
I disconnected the Vin pin. Connecting only the 5V pin from the 7805 stmicro voltage regultator I noticed that the board draw 0.45A! I jumped from the chair. I disconnected every output from it and it still draw 0.45A. It's hot as hell. I first noticed this problem smelling something in the air.. just a little smell of hot plastic... no smoke... touching the 7805 IC I understood something went wrong. I added a dissipator to it. Then I tried to touch the nano. It was super hot.
I disconnected the 5V pin, I connected the usb cable. Still super hot. I don't know if it has always been that hot since I bought it. The board is basically new so I don't know if it's a manufacturing problem.
When the usb is connected Vin = 4.4V
I bought a new one and in a few days it will arrive. This board will be returned.

It is not so strange...  Remember what I said here below :

(Don't take this as an "I told you so", that is not my intend.  I wrote this as info you will need when you get the new NANO.)

...
(Question 1) With your 9v power supply, how many mA/Amp can it support?
The 4.5v you measured off USB supply is lower than expect, perhaps you are drawing more current than the 9v can put out.
...

[bold added to quote]

Your USB has a current limit and your 9v power brick (combined with the voltage regulator on your NANO) doesn't.

So, when connected to your USB, when it exceeded current limit, the USB port would begin to lower the voltage to keep the current at 500mA which is the USB specified current limit.  Whereas, when your 9v brick combination is overdrawn, it probably just poop-out to below what can support your NANO+plus your other stuff on the breadboard.

Now you use a 7805 which can push out a lot more than 500mA, things got cooked.  Perhaps had your 9v been able to put out 1A+, the cooking would have begun with the 9v power supply,.

You have something not well there.  It could be a simple short (one time I had a piece of loose wire got in the space between the breadboard and the bottom of the NANO), or a short/failed-component elsewhere on the NANO or the breadboard.  The voltage regulators do fail - I had the voltage reg on a NANO failed before, which was found and replaced and the NANO is still in service.

When you do get your new NANO, first power it with your USB, that same USB port which worked (since it doesn't cook things) - solve that problem or your setup will just be a NANO execution device.  Check the USB voltage before and after you plug in the NANO.  If your USB is 5v+- 0.2v, and it drops all the way to 4.5v with the NANO again, you need to do more checking.  If voltage is about the same as before the NANO is plugged in, that problem may be gone but just "may be" so you need to continue in a check-mode - now try the 9v brick again.  Only connect your 7805 (no current limit there) when you are sure that problem is gone.

Oh, this is probably a lesson on the value of CC+CV power-supplies.  CC is a misnomer there, it is really a current-limit instead of constant current.  I would not hook up anything experimental until I set the current-limit to something I believe this device should not exceed (besides voltage, of course).

EDITed for wording error.

[Syntax Error]

Any guess what happened to my NANO?

I suspect you may have burned out the voltage regulator and some other parts if you connected the power supply direct to the 5V pin. A fail of the LM1117-5.0 would explain the high current consumption.

Get a replacement and be carefull to connect the power supply to VIN only.

I would like to add that I could find no official reference design (circuit diagram) from Arduino-Spa-Italy, anywhere online. The one @themadhippy links in the post above is for a classic Nano. There's not even a design on Github. I wonder... is there is a problem with the nano-every ?

[Rick Law]

...
...
I would like to add that I could find no official reference design (circuit diagram) from Arduino-Spa-Italy, anywhere online. The one @themadhippy links in the post above is for a classic Nano. There's not even a design on Github. I wonder... is there is a problem with the nano-every ?

I am sure they used to have one - I recalled reading it...  Wonder why it was removed.  Granted, they had some political fights within, but that really should not cause the removal.

I suspect they may be trying to sunset the old stuff so they can begin selling more new ones.

[oPossum]

Nano Every schematic https://content.arduino.cc/assets/NANOEveryV3.0_sch.pdf

[Syntax Error]

  Thanks oPossum. Life is easier a circuit diagram!

This explains why the green LED is on, as it's on the 3V3 regulator which is powered by the USB bus.

I note there's no polyfuse shown on VUSB, which was an Arduino signature feature.

The MPM3610 datasheet : https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MPM3610GQV/document_id/2090

[Lucky-Luka]

Just three things
1) The project is working right now with 5V connected to the 5V pin and no usb and no Vin pin connected. The board is scorching hot but it works... I assume it will not work for a long period of time though. Tomorrow the new board will arrive and this one will go to destination f@cked.
2) Even when connected only to the usb port (nothing connected to the board pins) the board gets extremely hot right now.
3) This is the history of this unfortunate NANO Every board:
    a) I programmed and run the project connecting only the USB as power source. I haven't measured the board temperature in this stage.
    b) When I finished the program I connected the 9V and disconnected the USB cable. The board didn't turn on.
    c) I connected the 5V pin and the board got super hot
    I can't remember a single wrong action in what I've done.
    Or a board manufacturing problem or I did something wrong accidentally and I can't remember it.

[james_s]

It sounds to me like the 5V regulator on the board has failed, or possibly the isolation diode is shorted. It should not be too hard to fix.

[Lucky-Luka]

Right now I've noticed that the 5v pin is shorted to the gnd pin!

[Rick Law]

Right now I've noticed that the 5v pin is shorted to the gnd pin!

It couldn't be a dead-short, if you really have a dead-short your NANO will not run at all since that would suck all the current leaving the rest your NANO with no power to run with.

Since you have another NANO coming, you can try clearing that issue with the old one - remove some excess solder or scrap it a bit with an ACTO knife or whatever.  That could be a good learning experience.

[westfw]

I note there's no polyfuse shown on VUSB, which was an Arduino signature feature.

I don't think any of the "Nano" Arduinos (official or clones) has had a polyfuse...

[Syntax Error]

I don't think any of the "Nano" Arduinos (official or clones) has had a polyfuse...

You're right. I was thinking of the Pro Micro which does.

@Lucky-Luka I think your answer can be found here: 10 ways to destroy an arduino :
https://www.rugged-circuits.com/10-ways-to-destroy-an-arduino

[james_s]

Some of the clones at least use a rather crappy regulator. It's supposed to be good for something like 16V but I've popped a couple of them by connecting a 12V battery that wasn't more than 12.5V. I've never had that happen with other similar 3 terminal regulators.