frequently asked questions - MCU connection issues

I have been working on a FAQ for this: I hope some of it helps
* MCU POWER JUMPER was not actually removed. If you don't remove this jumper, the Octopus board is unable to use USB to communicate with the PI * edit your printer.cfg. If you didn't edit your printer.cfg to match your setup, klipper will be unable to connect to the octopus board. Go through each line of the printer.cfg file and uncomment the lines that are needed for your setup. * Bad wiring. There are several warnings about fixing the endstops wiring. If you fail to do this you will short your board and cause damage. There may also be other wiring/shorts. If you are still having issues disconnect everything but power to the octopus board and the USB to the PI and then try again. If the PI complains about temperature out of range (this is expected because you disconnected your thermistors) then you know you had a wiring issue. Shutdown and reconnect one item, then turn everything back on. Continue to do this until you get the MCU connect error again, and whatever that last item you connected is the problem. * Bad USB Cable. You need to connect USB A (the Big rectangular plug) on the PI, and USB C (the very small plug like the one you use on your cell phone) to the Octopus board. If you already have it connected like this, try a different USB Cable as the one you are using might be broken or power only.
If none of that still fixes your issue, you will need to SSH into your raspberry PI and run some commands: * SSH into your PI * disconnect your octopus board * run dmesg -w and while it is running, plug your octopus board into your PI * examine the output and see if there are errors trying to connect. If there, it will depend on the error what the next step is.
18 Replies
inland-turquoise
inland-turquoise2y ago
OK, thanks! I have lots of images showing jumpers on the Octopus PRO, but none of them show the location of the MCU POWER JUMPER. Where is it please? Thanks again!
blacksmithforlife
Check the owners manual
miklschmidt
miklschmidt2y ago
It's a V_USB (will be called similar in the manual / pinout) jumper, all it does is connect 5V with USB 5V (you don't want this and 24V connected at the same time).
inland-turquoise
inland-turquoise2y ago
Thank you, Sir! Please, I need some help. The Octopus PRO Manual, and dozens of on-line images of Octopus PRO wiring make no mention of this jumper. This is my first 3D printer, but I have been building electronics, and writing computer code for about 50 years. I've built a Standard Rat Rig V-Core 3 500. My problem is that Klipper won't start. I have a Raspberry Pi 3 B+ connected to the Octopus via USB-C. There are several LEDs illuminated on the Octopus, including green motor power and a rapidly flashing red "STATUS" LED. I have a Windows 10 lap-top that appears to be communicating very well with RatOS via WiFi. Since I had no knowledge of this jumper, have I damaged the Octopus? Thank you for your help, Mr. MiklSchmidt!
blacksmithforlife
please start a new post
narrow-beige
narrow-beige2y ago
OKay, I had figured out that hotend thermistor 's wires was connected and that was a shortage in the wiring.
lillian
lillian2y ago
hi i followed your procedure , thx its well described , but i cant ssh into the pi: when i get "[email protected]'s password: " i can't type anything behind this line ? would you like me to open a new post ? EDIT: since the post i got to ssh and enter the command and i got no error, what would be the course to get the cu to connect then ?
miklschmidt
miklschmidt2y ago
Use the configurator and follow the instructions to the letter. If it won't detect / flash correctly, try different sd cards. It's important that you do exactly what it says.
lillian
lillian2y ago
ok i tried redoing everything now i can't pass step one : "BIGTREETECH Octopus V1.1 was not detected"
miklschmidt
miklschmidt2y ago
That means it didn't flash correctly. All your wires are removed, sd card is formatted correctly and you tried different cards?
lillian
lillian2y ago
ok gonna do another card thx
blacksmithforlife
you probably should start your own post instead of continuing in the FAQ
Torque
Torque2y ago
If using DFu mode do you need an sd card inserted?
blacksmithforlife
please make a new post
flat-fuchsia
flat-fuchsia16mo ago
hi I need help to fix the mcu connection I did searched all the web and didn't find a fix to it pls help me
No description
flat-fuchsia
flat-fuchsia16mo ago
and I did checked the ratrig form for it and no luck with it
blacksmithforlife
blacksmithforlifeOP16mo ago
start your own post please
flat-fuchsia
flat-fuchsia16mo ago
ok
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