I have been building a pen plotter with UNO (board 1, a clone) and CNC shield kit brought from Ooznest.
I have successfully tested the motor and servo are all working through USG on a MacBook Pro M3 via USB C hub.
However, after I accidentally pulled the cables and the UNO (board 1) CNC shield stack fell off the desk, (it did not hit the ground, just hanging by the cables) the board stop connectting to the USB port, and the L, TX and RX leds are now always on when I plugged it in.
I tried to plug it into an older MacBook with USB A port, but the Arduino IDE 2.3.2 won’t detect it via the USB A neither, and all the 3 leds are also always on.
I found a much older UNO R3 board (board 2, not a clone) in a box which was never used. This UNO board does being detected by both laptops. But it wouldn’t receive the Grbl FW when I upload it via either laptops and constantly giving me the same error message “ avrdude: stk500_recv(): programmer is not responding”
So my questions are:
Is board 1 toasted? Will I be able to reset it?
Why is board 2 giving me the error message? It was never used. Will I be able to reset it?
If the answer is I will need to buy a new UNO board, should I get the R4 so maybe I can work with WiFi, or I should stick with R3? (The CNC shield is modified to take power from the Arduino UNO Vin pin via a power adapter on the barrel jack.)
Let’s troubleshoot the issues with your Arduino boards step by step:
Board 1 (Clone):
The constant illumination of the L, TX, and RX LEDs on board 1 indicates a problem.
Try the following:
Disconnect any wires connected to the RESET pin.
Check the power supply. If using a USB cable, try a different cable or USB port.
Remove any black packaging foam attached to the board.
Test the board on another computer to isolate the issue.
Board 2 (UNO R3):
It’s unusual for an unused board to give the same error.
Ensure you’ve selected the correct board type and processor in the Arduino IDE.
Try burning the bootloader using another working Arduino (e.g., the UNO R3) to see if that resolves the issue.
Choosing a New Board:
If you need to replace a board, consider the Arduino UNO R4:
It features a 32-bit 48 MHz Arm Cortex-M4 microcontroller, offering more performance.
It has a USB-C connector, RTC, real DAC channel, and CAN protocol support.
The WiFi version includes an ESP32-S3 chip and an onboard 12×8 LED matrix.
Remember to follow the steps carefully, and I hope you can get your plotter up and running smoothly!
you can replace ATMega328P chip, but you must be sure it is really dead, try to reflash bootloader with external USB-to-UART module or with another board with sketch "Arduino As ISP" in it.
Board 2 is not the same error, two laptops can detect it via USB C or USB A.
but it doesn't allow me to upload the Grbl on it. I will try another simple sketch when I get a chance.
Board #1
If UNO board #1 is a clone, then it likely uses one of the CH340 type USB-Serial interface chips. If the board is no longer detected by your PC and it fell off your desk/bench as you described, then I would be looking at the USB connector to see if any of the solder joints have broken or sheared off first before looking at the 328P.
Board #2
If UNO board #2 is an old board, then I wonder if it has an older bootloader installed. I seem to recall this occurring with an Arduino Nano - and there is even an option in the IDE (v1.8.19) Tools->Processor menu to select an 328P with an old bootloader. There's no option for an old bootloader on an UNO in the IDE, but since the Nano and the UNO use the same processor, you could try telling the IDE you have a Nano with the old bootloader and try loading the blink sketch to see if that works.
Board #1 is a 328P, nothing visually broken, and it had 3 leds on when i plug it into the USB. So I assume it is something deeper than a solder joint.
I tried the method on this page to try burn the bootloader from Board #2 to Board #1 but it returns an error: Failed chip erase: uploading error: exit status 1
I also tried a couple of options of using Leonardo or nano with board 2 but no luck of uploading the Grbl on it. is there anyway I can update the FW in board #2?
I can upload a simple sketch to board 2. But when I try using the Firmware updater it just says no board detected...
Or does it just mean I can make a decision to buy a new UNO R3 or R4?
