Mini-Rambo board not moving stepper motors - Initial build

Hello, thanks for the assistance in advance!

I finally assembled the MPCNC hardware. Trouble with the mini-Rambo board.

I have loaded the Arduino software for windows, and the driver for the Rambo board on my Window 7 laptop.

Windows sees the board ok as it shows up in the devices page without errors connected on Com4 via the USB port and cable.

I have downloaded and installed Repetier software and set it up as described on your website. The motors are connected with the wiring kit you supplied in the kit.

When trying to test the motors using the manual control, nothing happens. I have tried to reverse the wires as suggested in moving in the wrong direction, but nothing happens. There appears to be power on the board, as the green led is lit. The yellow led lights momentarily on power up. Do I have a defective board???

What is next?

Thanks for your help!!

First thing to check is the power supply, and that little green adapter, those have a high failure rate that is why they are free and not in the instructions.

as stated above… “Windows sees the board ok as it shows up in the devices page without errors connected on Com4 via the USB port and cable.”

Also, the green power led on the board glows proudly when the power supply is plugged in.

Do you have any other computer that has a more recent OS? Windows 7 is a different beast that I have not used in many years and I am confident things like repetier and not concerned with backwards compatibility with it. We know Vista does not work, maybe 7 is on that list now as well.

As I said I have tested that board and it works when it left here. LCD?

Just to be clear, you don’t have repetier server installed, do you? It will take over the port and not let host see it.

Can you post the console log from repetier host? It is at the bottom of the screen, I think. Just the log from it connecting, and after you move it a bit with the manual buttons.

The Control/LCD screen I ordered arrived yesterday. I connected it to the mini-rambo and it showed up ok… I was able to move the motors manually with this method. Great!

Do you have documentation to align all the axis using the LCD? I would like to install some endstops, but not sure if this board will support this…

I will try and struggle along with the usb setup…

1 Like

Here’s what I do (I don’t have endstops).

  1. Pull the machine to a start corner. There are some blocks you can print, but you really just want to make sure it starts square. A tape measure is good enough for a lot of work.
  2. Power up the machine, and use the lcd to move away from the corner. Thia will energize the motors and they will stay in lock step as long as they stay energized.
  3. Use the lcd to move the bit to the 0,0,0 location. Since you need to use the lcd for this, it is easier to mount the work near that corner.
  4. Set the home position here.
  5. lcd move up a little
  6. Start the spindle, Print from SD card.

You can also push the gantry to 0,0,0, and then use a tape measure to square it up, then just do a little movement to enable the motors.

Thanks for the assist and your expertise! At last, I can try and finish this exquisite puzzle…

After much struggle, I found out, through the forum posts, that the mini-rambo board is flashed from V1 with a static baud-rate of 250000. Why so high?

Re-flashed the firmware with the baud-rate set at 115200. (something a PC can appreciate…) All is well now.

FYI,… this little tidbit of information should be mentioned on the website build page for us “noobs”.

Thanks!

I haven’t seen or heard of any problems with 250k. The USB serial port should handle that easily. Are you sure you just didn’t change it to 250k in RH?

They’ve been 250k from the beginning. Unless you’re running this from a 486, your computer can handle that speed.