Troubleshoot Lulzbot Mini: won't connect to printer

Hi, I’m a public librarian trying to put on a program where teens can design an object in tinkercad and I will use our Cura Lulzbot Mini to print it for them. Nobody on staff knows how to use the printer, or knows if there was a designated computer to use with it (it is an old model without the attached screen). It hasn’t been used in at least 3 years. I downloaded the updated Cura software 3.6.37 but it won’t connect to the printer. I tried using a different USB cable and/or plugging it in to a different USB port on the computer to no avail. What should I do? Does the firmware need to be updated? If so, I imagine I’ll need to download an older Cura version to do so. How do I know which one to use, and where to download it from? I’m lost and would greatly appreciate any guidance. Thank you!

The current version of Cura (3.6.37) can flash the Mini.

Given that you’re at a public library, my first guess would be that the computer you’re trying to plug it into is a managed system with restrictions on USB that are preventing it from connecting.

If you can connect it up to a personal laptop, or that you can be sure isn’t restricted, that would go a long way toward helping diagnose.

There’s always the chance that the reason it wasn’t touched for three years is that somebody broke it. If you can give your location, there may be somebody in the area that can give you additional help.

You mentioning that it hasn’t even been used for several years reminded me of one possibility.

Some of the very early Mini 1 printers don’t connect at the same baud rate. You have to go into the machine settings in Cura and change the connection speed from 250000 to 115200. Then you can flash the firmware. With new firmware loaded, you will need to go back and change the connection speed back to 250000 since that is what the new firmware connects at. Worth a try if it is an early Mini 1 printer.

If you need more detailed instructions on how to change the connection speed just let us know and I, or someone here, can help further.

The Mini 1 is a bit temperamental when it comes to updating for a new software.

Please follow these steps without deviation.

-Disconnect the printer from your computer.
-Uninstall whatever version of Cura you have installed in your computer
-Clear your computer’s cache of any Cura files using the instructions at the bottom of the Cura page under “Troubles Upgrading? Clean Your Cache!”

-Restart your computer.
-Install Cura 3.6.37
-Open Cura
-Plug in your printer to your computer. DO NOT CLICK CONNECT ANYWHERE
-Set up your printer by following the printer setup prompt.
-Click finish on the screen that pops up.
-Go to Settings > Printers > Manage Printers.
-Make sure the correct printer is highlighted in blue and click Upgrade Firmware.
-Select the box that says “Update EEPROM”
-Click Automatically Update Firmware.
-Wait for the update to finish.

You should be connected once the firmware finishes.

how do i change the baud rate in cura 3.6.40

Baud rate is changed in the Machine Settings page.

In the top left menu bar click Settings, then Printer, then Manage Printers. (Or a shortcut is to click the green block on the top right that shows the printer name, then click Manage Printers.)

On the page that pops up, click the Machine Settings button.

The window that pops up will be sized to small to see the baud rate selection, so grab the scroll bar at the bottom and drag it right to scroll over to the right and you will see “Communication Speed:” with a drop down below it. Click the down trangle after the number and select the rate you want.

Really old Mini 1 printers need 115200. Anything remotely recent should use 250000.

what cure version is this with

In the stable (3.x version) of Cura. As @cdsmith said, the window that pops up is too small to see it without resizing.