I’m new to working with SKR boards/CNC in general. I’ve loaded the FIRMWARE.bin file onto an sd card (64 gb but partitioned to 4096 mb), but nothing happens when I power it on.
I have followed the wiring instructions for the MPCNC Primo exactly (triple checked) and have the screen disconnected. When I connect the 5v power into the wall nothing happens on the board, but when I connect the SKR to my computer via USB the D4 light turns on red.
Any advice on what I might be doing wrong?
Welcome to the V1 community forums!
I’m sure we can sort out the issues you’re having with the board.
You need to use an SD card formatted with FAT32, no larger than 32Gb. An old Class 4 card in a much smaller size is way better than a new one.
SKR power is 12-24V, 5V power won’t turn on the voltage regulators in the board.
Post a picture of your SKR Pro 1.2 wiring, and confirm what voltage your power supply is putting out.
Where did you get your SKR pro from?
If from V1, it’s already flashed.
I ordered from V1 but there was no SD card in the board.
The power supply is wired to 1&2, then 1&3 and 2&4 are connected. The stepper motors are wired the way that the documentation recommends. I need to find connectors for the endstops so for now I was just using the firmware.bin file that doesn’t use them. When I plug the power supply into the wall no lights turn on. The red light (D4) just above the port with the blue wire in that photo turns on solid red when I connect the cable to my computer’s USB port.
If nothing seems off with the wiring I’ll buy a smaller SD card and see if that works.
If the LEDs aren’t turning on no SD card will help.
I’d recommend you pull the wiring back off the SKR, then with the wires isolated measure the voltage coming from your power supply.
I’d also check all the fuses on the board.
Something is completely amiss with this setup.
Checked the voltages and I think I figured out what the issue is. There’s 12V coming out of my power supply, but when I hook up the connector below nothing comes out. I’ve tested it both with the wires attached and just sticking the multimeter needles directly into it and it was 0V either way. Could it just be this piece that’s faulty?
This was the issue. I used some electric tape and connected the bare wires directly to the plug from the power supply and all the lights now turn on the board.
I try to avoid those connectors.
I’ve had nothing but trouble with the import version of those connectors, so I won’t use them.
For me, I’d use a ring terminal crimped to the PS wires and make a jumper wire set with ring terminals between board power and motor power.
Also, I note in your picture that there is stranded wire going into a screw terminal.
That’s not best practice. Over time, the twisted wires will compress, and that loosens the wire in the terminal, allowing it to work out.
Far better for that is either to use a crimp ferrule (if you want to keep using screw terminals), or switch to a terminal block that uses lever or spring clamps to secure the wire. Those keep constant compression on the twisted wire so that problem goes away.
Thanks for the help. I was planning on replacing the twisted wires, just didn’t have anything else available and wanted to make sure I assembled everything correctly.
Endstops are only used during homing, and you cannot not electronically home without them. That means there is no reason to reflash the board. Just don’t home your machine until you have the endstops installed.
If you want to use your machine before you have endstops wired, you can either 1) not worry about it (only some projects need the squareness of homing), or 2) install some sort of blocks to push against and engage the steppers when the axes are resting against the stops. It was pretty common in earlier versions of V1 machines to not have electronic endstops.
The problem is that you left a bunch of bare wire sticking out from the green screw terminals , and they are touching each other and shorting out (hence the 0 volts).
Wiring directly to the SKR board is probably more reliable overall, but with proper installation, the barrel connectors are fine to use (just don’t leave any exposed wiring).
