Replace crystal on arduino Nano or downclock to 8Mhz possible?

Dear Arduino community,

I’m requesting some help because I have a little issue on one arduino Nano V3. after A LOT of troubleshooting I simply saw that the oscillator feeding the 16Mhz to the Atmega has disappeared…(bad solder maybe).

I have two question for you :
1 : is it easily possible to find some replacement oscillator for this board? and if yes, which model should I take?

2 : otherwise and if cost and constraints to solder a new crystal are too important, should it be possible to down-clock the board to the 8Mhz (if the chip have an internal 8Mhz clock as I saw during my forums research)?

Thank you in advance for your help,

Rgds,
Sebj

Look at the data sheet. I'd think that the board uses a ceramic resonator, not a crystal. You can try a replacement, but possibly more than only the resonator is defective. AFAIR the bootloader uses the RC clock, can you upload a sketch to the board?

should it be possible to down-clock the board to the 8Mhz

Yes, you can set the fuses to use the internal 8 MHz RC clock.

If the crystal/resonator or internal clock is not working, you need to apply an external clock signal during the fuse programming operation. The operation is easy to do, and is described in this blog article:

DrDiettrich:
Look at the data sheet. I'd think that the board uses a ceramic resonator, not a crystal.

Note that the ceramic resonator usually includes its own capacitors, but a crystal will require these.

Thanks to all for theses quick feedback. I'll take a look on both solutions (replacement vs down clock).

@

DrDiettrich:
Look at the data sheet. I'd think that the board uses a ceramic resonator, not a crystal. You can try a replacement, but possibly more than only the resonator is defective. AFAIR the bootloader uses the RC clock, can you upload a sketch to the board?

Yes I confirm you that the resonator is no more present on the board (CF attached picture) impossible to push any sketch and even not possible to push new bootloader. I've also confirmed that there is no more clock on pin 7 of the atmega with an oscilloscope control. I hope it is not too hard to place an external resonator as everything on the nano is really small (not well equipped for CMS soldering)

I would carefully examine the pads where the resonator was. If it was forcefully knocked off the board then the pads may have been torn off, which makes the repair much more difficult, since you would need to tack some wires directly to the microcontroller pins or scrape the solder mask off the traces to get some bare copper to bodge solder a resonator to. That fix would likely be fairly fragile.

In that case, it might be best to instead just switch to using the internal oscillator. To do that, you will need to provide a temporary external clock source on the clock pins of the ATmega328P, since the fuses are set to use an external clock source and the chip is "bricked" without one. That will still require connections to the clock pins, but those connections only need to work long enough to set the fuses for the internal oscillator. So you could tack some magnet wire to the pins on the ATmega328P and not worry too much about getting a perfect soldering job as long as it doesn't cause shorts because you're just going to remove the wires as soon as the fuses are set.

pert:
I would carefully examine the pads where the resonator was. If it was forcefully knocked off the board then the pads may have been torn off, which makes the repair much more difficult, since you would need to tack some wires directly to the microcontroller pins or scrape the solder mask off the traces to get some bare copper to bodge solder a resonator to. That fix would likely be fairly fragile.

In that case, it might be best to instead just switch to using the internal oscillator. To do that, you will need to provide a temporary external clock source on the clock pins of the ATmega328P, since the fuses are set to use an external clock source and the chip is "bricked" without one. That will still require connections to the clock pins, but those connections only need to work long enough to set the fuses for the internal oscillator. So you could tack some magnet wire to the pins on the ATmega328P and not worry too much about getting a perfect soldering job as long as it doesn't cause shorts because you're just going to remove the wires as soon as the fuses are set.

Thank you Pert.
I'll check the pad of the old resonator. I may be lucky to be able to solder a new one over (or place a temporary clock to change the fuses).

I'll let you know the solution adopted once done.

thanks you all for the help

Sebj

Screenshot_20190703-194747.jpg

sebj84:
Yes I confirm you that the resonator is no more present on the board (CF attached picture)

I don't follow. :astonished: What is that white ceramic thing with the two gold pads?

Didn't look at your image earlier. :roll_eyes:

my nano has a metal cap.
makes me think the resonator cover was lost.

nano with resonator.jpg

nano with resonator.jpg

Metal caps are expensive, cheaper source wins.

Yes I confirm that the oscillator has gone... Low cost nano... It took me some time to discover that... The only one advantage is now I'll maybe able to solder a new resonator like this one over the metal we can see : https://www.google.com/search?q=16mhz+resonator&client=ms-unknown&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwi9oPuR4ZvjAhXQyYUKHZmBAdIQ_AUoAnoECA0QAg&biw=412&bih=695&dpr=2.63#imgrc=EV1jIGjZsJGrNM

In same time I'll check if I can generate a temporary ext clock to activate internal 8mhz

It's fun to try but the effort of sourcing a new part and removing the old resonator is not worth the ~2-3 USD it takes to buy a complete new Nano. That's about the price I paid for my Nanos... and they have resonators with metal cap.

sebj84:
Yes I confirm that the oscillator has gone... Low cost nano... It took me some time to discover that... The only one advantage is now I'll maybe able to solder a new resonator like this one over the metal we can see

The point is - according to that photo - it has not "gone"! Something is there, attached to the PCB.

It is not a matter of "soldering over it"; something is attached to the PCB. If it is not functional as a resonator, then you need to remove it in order to attach a working one.

wvmarle:
It's fun to try but the effort of sourcing a new part and removing the old resonator is not worth the ~2-3 USD it takes to buy a complete new Nano. That's about the price I paid for my Nanos... and they have resonators with metal cap.

But isn't that what we are all about? Having fun?

I certainly would not be doing this in an attempt to make money. :astonished:

Paul__B:
The point is - according to that photo - it has not “gone”! Something is there, attached to the PCB.

It is not a matter of “soldering over it”; something is attached to the PCB. If it is not functional as a resonator, then you need to remove it in order to attach a working one.
But isn’t that what we are all about? Having fun?

I certainly would not be doing this in an attempt to make money. :astonished:

Yes off course I’ll check this “support” with multimeter to see the properties of it before soldering over it. There’s maybe some capacitors or any sort of components inside it…

For the second part yes I confirm it’s only for fun and learning… Maybe one day it will be useful knowledge to mount my own atmega board or other type of u controller

sebj84:
Maybe one day it will be useful knowledge to mount my own ATmega board or other type of u controller

I consider that a major waste of time - and money.

These boards - at least from China or should I say direct from China - are cheap. Consider them a functional component; something you use as part of a system to perform the task you want in the most efficient way. You do not need to assemble your own to understand how it works nor to make it work "better"; the designs available are tested and stable.

It makes no sense to design the raw ATmega chip into your own PCB (unless like a couple of the posters here, you intend to actually make have them made (in China) in quantity to sell), just buy cheap Pro Minis or Nanos and mount them to your own PCB. stripboard or just protoboard.

Paul__B:
just buy cheap Pro Minis or Nanos and mount them to your own PCB. stripboard or just protoboard.

My usual strategy as well. Works like a charm.

wvmarle:
My usual strategy as well. Works like a charm.

Paul__B:
I consider that a major waste of time - and money.

These boards - at least from China or should I say direct from China - are cheap. Consider them a functional component; something you use as part of a system to perform the task you want in the most efficient way. You do not need to assemble your own to understand how it works nor to make it work “better”; the designs available are tested and stable.

It makes no sense to design the raw ATmega chip into your own PCB (unless like a couple of the posters here, you intend to actually make have them made (in China) in quantity to sell), just buy cheap Pro Minis or Nanos and mount them to your own PCB. stripboard or just protoboard.

Fun and learning…

I know (and I do it for any projet I have) that I can buy Nano’s (or any others Uc boards) for only few $.

So just to come back on the original question the response is “YES” we can replace “oscillator” on the nano and “YES” we can easily downclock to the internal 8Mhz the nano.

What I did is :

2 - From the working arduino (with Gammon sketch), I’ve put Pin 9 that is delivering a 8Mhz on the “white pad” that we can see on my picture (slot where was the lost oscilator). I’ve confirmed that this is only a simple support without any more component inside that is only deserve as an oscillator support. I’ve placed the pin 9 “by hand” on the plate that was connected to pin 7 of the Atmega (XTAL1 of the atmega328P).

3 - once done I’ve used the option “Type ‘L’ to use Lilypad (8 MHz) loader” in the serial console (witch Gammon sketch running)

  • To upload sketch on the restored nano :

4 - once 8Mhz bootloader was well installed on the failed nano I had to add a 8Mhz breadboard into the arduino IDE (followed the 8mhz breadboard installation on IDE : https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard)

5 - tested the blink sketch and TADA! working…

So yes I confirm that was a waste of time… Because it took me 2 mins only to order 10 new nano’s on a chinese site… But I confirm also that was fun and really instructive to troubleshoot this issue with your help.

Great work resurrecting your Nano sebj84! Sometime I like to try to fix things even when it's not economically sensible just to feel I had a small victory against our culture of replace instead of repair.

sebj84's Screenshot xtal.jpg:

pert:
just to feel I had a small victory against our culture of replace instead of repair.

Exactly!

And I would of course, do the same, for the same reasons. In addition, it now works on 3.3 V such as a lithium battery. :grinning:

I remain fascinated by what that ceramic platform with two pads is as I presumed it would be desirable to remove it (if replacing with a crystal). If it is the mount for a ceramic resonator which is a three terminal device, then it must contain (or in fact, be) the two loading capacitors for the resonator itself. Presumably you could solder to one or both pads if needed, though I suspect that would cause it to come loose from the board anyway.

Note my comment on grossly wasting time and effort referred to constructing your own Pro Mini clone or sub-assembly, not to repairing this board. :sunglasses: