Working on a couple Athena Printers for local high school - need to know where to start

[Jon Genow]

I've got two Athena Franklin printers, built around 2016 if the teacher that owns a third remembers correctly.  Melzi 3.0 boards with a Beaglebone green sbc.  The two I'm working with don't currently operate.  I've gone thru the first one and determined I've got a short somewhere in the hotend wiring as well as the cooling fan wiring.  I haven't assessed the second one yet.

My reason for messaging - the Melzi has a usb port.  What's the baud rate to connect to the Melzi via putty, or is that not possible?  Second question - I've got a spare Pi3 - if I were to hook that to the Melzi USB port is it possible to skip the Beaglebone, or is the firmware not configured to communicate directly with something like octoprint?

Next reason - is there a repository somewhere to find all the printed parts so I can reprint cracked/broken pieces?

thanks in advance
Jon

[Dr. Bas Wijnen]

Hi Jon,

It's always fun to repair things, especially when you can expect to be
successful. :)

As for your questions, I'll answer them in turn.

For context, I'm one of the designers of the machine. In particular I've
written Franklin, which is the firmware and host software that we use to
control them.

> My reason for messaging - the Melzi has a usb port. What's the baud rate
> to connect to the Melzi via putty, or is that not possible?

Depending on what you mean, the answer is either that it's impossible, or that
it's your own choice. The Melzi contains an avr microcontroller just like
Arduino boards do. That's a pretty weak device. It does not support running an
operating system where you would be able to get a log in shell.

But perhaps you meant that you wanted to send G-Code to it? Whether that is
possible and what the settings are, depends on the firmware. Franklin's
firmware is designed to only communicate with its own host software. It's a
binary protocol that you could never manually enter using a keyboard.

But if you install different firmware on the machine, it will do whatever that
firmware wants. Everything, including the baud rate, depends on what firmware
you are uploading.

> Second question - I've got a spare Pi3 - if I were to hook that to the Melzi
> USB port is it possible to skip the Beaglebone, or is the firmware not
> configured to communicate directly with something like octoprint?

Using any other host computer should be fine. The firmware is not configured
for octoprint, but it can be replaced. I'd like to suggest that you can also
keep using Franklin; it has similar features to octoprint in terms of running
jobs over the network. Personally I prefer the way it allows changing the
machine's settings while it's printing, this makes for very easy calibration.

A side note on that however: this functionality has been broken for a few years
now. But it sounds like your system wasn't updated since 2016, so it should
still work without any major issues.

Another side note is that I've recently fixed all of that and am currently
testing it out before I release it. Anyone who wants to try it out before that
can get the code from the "broken" branch on github. (It's called that because
I make zero promises of the code in that branch working; right now I'm feeling
pretty good about it though.)

So stay tuned, I'll post about the release in a separate message soon.

> Next reason - is there a repository somewhere to find all the printed parts
> so I can reprint cracked/broken pieces?

Yes, there is. The files for Athena are at https://github.com/phidiasllc/athena
Those may be slightly updated from what's currently on there, but my guess is
they will fit as replacements.

I made a fork of the system where I improved some things (at least I prefer the
changes, of course). Those files are at https://github.com/zelfmaker/minerva

Enjoy this project and please let me know if you have any more questions or
issues.

Thanks,
Bas