Spark and Pop and Dead Machine

So, I killed My machine.

I was cleaning the extruder with the wire brush (see picture) while it was heated up and there was a spark and a pop and the machine died. Plugged a different functional power supply into it and it does not power on.


  1. Never ever ever do this.
  2. You at a minimum killed one or more fuses. You may also have killed either the thermistor or the heater core. There are fuses in the following locations:
    a. Large fuse in the electronics enclosure
    b. 2 small grain of rice sized fuses in the electronics enclosure (be very very very careful removing these. If you accidentally get one of the metal fuse contact plates and yank it out of the board, it is expensive…)
    C. There may or may not be a larger fuse in the power supply at the plug location. I can’t remember if the TAZ has one there or not.

Replace all of those fuses. if it still doesn’t power on at all, you could have a toasted Rambo board, which can be sourced from either lulzbot or ultimachine if you want the exact same stock board. The machine should still power on even if the thermistor or heater core are toast.

Piercet is correct, most likely a fuse and hopefully nothing more. Fuses 4 reference:

It will most likely be your F3 fuse, as nothing will turn on. If you don’t have access to a multimeter to check for continuity (ohms), you can swap the F2 and F3 fuse to verify. This will allow the printer to turn on, but will not allow motor movement. If the fuse is blown, you can find replacements here:

I hope this helps!

Do you by chance carry your TAZ around using those wires as a handle? From that photo it looks like 2 of the 4 have the conductor exposed, and one is completely disconnected? I would also suggest replacing the hotend / fixing those connections PRIOR to attempting to restart the machine. This is not a Lulzbot branded Hotend but it should be the same

Never do this heard.

Thanks for the help. I ordered fuses, and a new hotend (i have been thinking on a new hotend for a while.) Hopefully, they will be in this week.

I have more TAZ problems I need to work out. Lots more. I gotta write up a new post.

Fuses came in the mail, and they fixed the problem. Runs like a charm.

I got this metal extruder recently and it is partially put together. I have printed a new extruder it needs and it appears to be functional (i.e. filament can traverse from the extruder into the hotend while cold.)

Current State

I need to get the fans working. This video just uses one big fan on the radiator, mounted to two holes in the extruder. I cannot find a file for this extruder with two holes (I can look harder). I could modify my existing files if I need to; I have the brass inserts. Alternatively, this image of the similar new lulzbot extruder has two fans, with one fan mounted on the traditional taz fan mount. I don’t know how the small fan is mounted.

Electronics and Firmware
Upgrading the Taz 4 to a metal hotend has this guide.

This Comprehensive List of TAZ modifications thread doesn’t have an upgrading a Taz3/4 to a hexagon hotend page. I submitted a request for one. It appears to be not-uncommon, so I figure the knowledge is in the forum somewhere, but I’ve haven’t found what I’m looking for in an hour of searching through the forum. I’m piecemealing knowledge from different threads and sources at the moment. A point in the right direction would be appreciated.

It’s in the OHAI kit section of the site, Specifically here: