Hot End Melted Itself

Hi, I recently came into possession of a second-hand AO-100, and was attempting my second print on it when the following happened:

I fired up the printer and it immediately said that it was doing a thermal shutdown, so I shut it all off and verified that everything was cool, then turned it on again to try the print, sliced the print with Slic3r, pasted the gcode into printrun, and told it to start printing.

The temps read out as if it were heating correctly up until 210 C, and then it sat there as if it were having problems getting past 210, it was going back and forth between 210 and 211. I let it stay there for a minute while I was googling the problem, then looked back at the bot and the hot end had melted itself. I looked back at the software and it still read 210, so I shut everything off, removed the hot end. Somehow it heated to at least 240 while still reporting 210, then some filament forced itself between the brass tube and the thermal barrier, and caused the hot end to start to push itself out of the thermal barrier at an angle.

It appears to be the same problem as here, only this person’s hot end didn’t melt itself:

Now I need to replace the hot end… I’ve got an old MakerGear groove mount hot end, but it doesn’t seem like the mounting plate for it will line up correctly with the extruder without some pretty good sized modifications, so I’m thinking I might just purchase a new Budaschnozzle 2.0c.

Will a Budaschnozzle 2.0c work as a drop in replacement on the AO-100?

Also, I don’t know what happened to cause the temp to not report correctly, is there a troubleshooting guide somewhere I could use to diagnose that and make sure it doesn’t happen again with the new hot end?


A 2.0c will work, but the connection wire colors are different. the old AO-100 didn’t have a disconnect fitting for the hot end assembly, so you will need to fit one to it to be able to plug the hot end in. You will also need to make sure the thermistor wires go to the thermistor leads, etc. instead of orange to orange, it’s going to be orange to red because of the color change. but you will want to verify that before proceeding.

Ok, thanks! 2.0 hot end ordered… I will hook it up as soon as it gets here. Is the problem likely to be a short in the old one, so I could hook up the new one and be good to go, or do I need to run a bunch of diagnostics on the electronics to make sure this doesn’t happen again?

Good news! The new Budaschnozzle 2.0c’s from Aleph Objects come with a wiring harness that is fully compatible with the original style AO-101’s. Just plug the red resistor wires and orange thermistor wires into their appropriate location on the board and you are good to go. If you choose to reuse your existing wiring harness, simply swap the red and orange pins on the Budaschnozzle’s Molex connector, and you can plug and play.

Here is the diagram for the connections on the RAMBo 1.0:

Thanks, I have an AO-100 though, it has connectors on half of the hot end, and crimps on the other, so I will have to install a new wiring harness for the side that was crimped. I believe the other side will be plug n play, based on what I’ve seen so far.

You’ll need to install 2 dupont-style female connectors on the thermistor, the orange wire pair. The red wire pair can be inserted into the RAMPS screw terminals.