Help needed on UNO Board

I am trying to put together a Laser Engraver which uses an Uno board and a CNC Shield. I not able to get it working. I have loaded the GRBL firmware on the Uno Board connected the motors to the shield and bench tested it and every thing works OK. I then move everything over the project and connect everything.(using the same motors). The Windows 10 PC sees the Com port and connects. Then when I try to move the motor the Com ports disconnects and that's the end of the Uno board. At this point after disconnecting the Uno board from the CNC shield and connecting the Uno to the PC the Com Port is not recognized.
I have gone through four different Uno boards with the same results. So I currently have four boards in which the Com Ports is no longer recognized (remember it was originally found). I tried two power supplies, two different USB cables, used different motor wiring looms and three different CNC Shields.
I can not figure out what is wrong... The UNO Board are original boards not third party.
It would be appreciated if someone could give me an idea of what could be wrong.
I would also like to be able to revive these four boards.

It sounds like something is messing up the bootloader. OR (worse) the oscillator fuses. If it's the first, you should be able to retrieve the boards by hooking them up using the ICSP header, and using 'burn bootloader' from the IDE. IF it's the later, read up on 'arduino high voltage programmer'.

Hi,
Welcome to the forum.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

How are you powering the motors and the arduino, are all the gnds connected together?

Thanks.. Tom... :slight_smile:

pdeyo:
I have loaded the GRBL firmware on the Uno Board connected the motors to the shield and bench tested it and every thing works OK.

I then move everything over the project and connect everything.(using the same motors). The Windows 10 PC sees the Com port and connects. Then when I try to move the motor the Com ports disconnects and that's the end of the Uno board.

Clearly you are doing something different in the second case - but you have not told us what?

What do you mean by "move everything over the project and connect everything"?
If it was already working why do you need to change anything?

My wild guess is that there is a short circuit somewhere or something similar that is overloading the Arduino.

...R

Thanks everyone for the guidance.
To answer some of the questions.
I tried to re-install the bootloader from Uno to Uno, but it does not work. I get the error 'Programmer not responding"
What is meant by "moving the board and motor on to the project" is I have the board connected to the PC via a short USB cable and the motors are connected to the with four wire hooked up via the cable provided my the stepper motor manufacture. This is where everything works. I move the motors over the project and bolt the motor to there mounts and connect the belts that move the X and Y axis rails. This is where the problems begin. I am using the same power supply 12v - 30a.
The wiring is simply ... Uno board with the CNC Shield on top. The CNC Shield has A4983 Stepper Motor Drivers installed. The CNC has three connections. One USB to the Uno board. 12V power to the CNC shield and two 4 wire motor connection cables connected from the CNC Shield to the motors.

Your error message when trying to load the bootloader usually means that it is not wired correctly. If the Uno in your device has a dip 328 chip, you can purchase one with a pre-installed bootloader, and just stick it into the socket on the Arduino board.

pdeyo:
What is meant by "moving the board and motor on to the project" is I have the board connected to the PC via a short USB cable and the motors are connected to the with four wire hooked up via the cable provided my the stepper motor manufacture. This is where everything works. I move the motors over the project and bolt the motor to there mounts and connect the belts that move the X and Y axis rails. This is where the problems begin.

That is not clear enough to be able to help you. Please make two drawings and post photos of the drawings.

For the first drawing show ALL the connections for the version that works.

For the second drawing show ALL the connection for the version that does not work.

AS WELL AS the drawings (but not instead of them) post a photo of each setup - i.e. photos of your hardware.

...R