Sorry to post more questions, but I’m so close!! I’m trying to get the MPCNC connected to Repetier so I can print my crown!
First: I’m using a RAMPS 1.4/Arduino Mega stack. Both are KeyesStudio brand-- gotta coordinate the colors…
Second: When powered from the 12V RAMPS barrel plug (but not connected to anything via USB), everything(display, steppers, etc) works fine. I can move all axes, no problem.
Third: When I plug in a USB cable WITHOUT 12V power, the computer can see the Arduino just fine as a COM port and Repetier connects to it happily, but nothing connected to the RAMPS is powered (obviously). Arduino IDE can also read and query the Arduino without error.
The problem: When BOTH 12V and USB are plugged in, the system disconnects and reads it as an “Unknown USB device” no matter what order the plugging happens. Am I missing something? A driver I missed, maybe?
I don’t think anything could be wrong with the regulator because the 12V power WILL power the Arduino, and the 5V rail shows 5V. EDIT: I should add when connected via USB and I plug in 12V, the display turns on immediately to the Marlin info screen, so I don’t think it’s even resetting the Arduino when it disconnects from the PC.
I thought I’d try to print it using the SD reader on the back of the display, but while the SD Card inserted message shows up, it still says “No SD Card” on the menu. It’s a 4GB, FAT32 formatted card that I use in my Marlin-powered.
Will, I got it to print in the most convoluted way possible. I connected Repetier without 12V power then used my variable bench power supply to carefully step up the voltage to see if I could get both Repetier and RAMPS working at the same time. Around 8V and everything was still working. I then used Repetier to load the crown file on the SD card and then chose “Print from SD” from Marlin, even though it couldn’t see the SD when Repetier wasn’t connected.
And, umm. It actually printed. There’s a little bit of distortion at the start, but I’m guessing that’s just the pen settling, since everything else is fine. Power draw was very constant at almost exactly 3A. So now I just have to figure out why everything gets so upset when the voltage gets too high.
Could the 5V regulator be freaking out and throttling itself to avoid blowing when 12V is connected? Could I supply 5V directly to test that?
Ok. All fixed. Just in case someone has a similar problem:
After more research I figured out that the Arduino was mad that it was getting power from both the RAMPS board and the USB connection. I desoldered diode D1 on the RAMPS board so that the Arduino wouldn’t get power from it anymore and voilà: worked just fine. Sorry I keep asking questions-- I promise I work on them for at least an hour looking for answers before I ask!
Don’t apologize. You had very valid questions and a tricky problem. I didn’t reply to you because I had no idea how to fix it. Now that you have it fixed I wonder if that diode was backward on the board.
I agree. there was definitely a problem with the board.
You should be able to connect everything and run the entire machine from any software like Repetier.
I am actually sworn off the cheap RAMPS boards. They work for a bit and then go kaput.
Spend the money on a Rambo, or try a Ramps direct from Ultimachine maybe.
Good job on getting it working though. I would not have thought of doing that.
I found the suggestion on a deep dive into the RepRap forum. I only really got the RAMPS board as a stopgap. It was $25 vs over $100, and I wanted to see how I did. Plus The Boss only gives me a limited stipend each month, so it saves me from having to wait until the end of April. ?
If I find enough projects for this to kill the RAMPS board, then I’m definitely switching to a better board!
