Arduino Nano Every doesn't work without USB connection

Thread Starter

Lucky-Luka

Joined Mar 28, 2019
86
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?)
 

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Alec_t

Joined Sep 17, 2013
11,295
Sounds like the on-board 5V regulator could be damaged. Did you at any point have the Nano powered by the 9V supply while the USB cable was plugged into both the Nano and the PC?
 

sagor

Joined Mar 10, 2019
207
Many wal-wart transformers have a much higher voltage under light loads. With no load, the 9V could read closer to 15V. The 9V rating you see is "9V at 1A draw". Less draw, and voltage will be higher. Also, make sure the 9V adapter is DC, not AC. Finally, verify the polarity of your wires when using DC.
It is entirely possible you blew the 5V regulator. Next time, measure the wall-wart voltage before using it... I have a 7.5V DC adapter rated 700mA. At no load, it shows 19V. With a small component tester, the tester reads an input DC voltage of 11.4V, mainly because I'm only drawing low current (less than 100mA). The voltage regulator on the component tester is rated maximum 35V input, so I'm ok, your Arduino regulator may not be that high a rating. The Arduino Nano AMS1117 5V regulator chip has a maximum 18V input rating, but usually they recommend input of 12V or less due to heat generated by the regulator. If your wall-wart supply gave more than 18V (no load voltage), you may have popped your regulator.
 

ericgibbs

Joined Jan 29, 2010
10,042
hi LL,
It is OK to have the +9Vdc on Vin while the USB cable is connected.
I will go with 'sagor' regarding the unregulated performance of many supposed 9Vdc PSU's when lightly loaded.
E
 

Thread Starter

Lucky-Luka

Joined Mar 28, 2019
86
I returned the NANO. Somehow the Vin pin and the GND pin were shorted. A new NANO arived and the problem isn't accouring anymore. I still don't know what happened the previous time. I will check the wall wart voltage output and I will tell you something if there is something as bad as you said (15V output). Thanks
 

ericgibbs

Joined Jan 29, 2010
10,042
hi,
I have had a couple of UNO's with shorted pins, on the TX/RX and A4/5.
Managed to clear the solder bridge short by lifting the plastic body of the onboard socket and scraping with small blade, between the pins.
E
 
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