TAZ 3 will no longer turn on

On Friday evening I was running a print and I went out to check on it and realized the printer had turned off mid print. I was unable to turn it back on. It is totally dead. I removed the side cover where all the wiring is and everything looked good. I have a spare fuse (already failed once before) and I replaced that with no luck. All connections looked good. I got out my multimeter and it showed zero power coming into the machine. I then thought I tripped a fuse on my house but after further inspection I found the wall socket was fine and the machine was getting power to it. I then shifted my attention to the 110v to 24v converter box. I noticed that the little green light that is always on when it’s plugged in was no longer on. Is it common for these converter boxes to fail? Any fuses inside? I have not taken it apart yet. I figured I would check on here first before I tore into the box. My hope is that this is some minor common thing with a simple fix.

I talked with Brent at lulzbot today. He thinks it’s the small white fuses on the Rambo. I didn’t even see those tiny fuses until he pointed them out in a picture. I’m doubtful they are the problem, but at $.99 a fuse it can’t hurt to swap them out. I will do that as soon as I get them in the mail and will report back my findings. He also told me that there are 2 fuses inside the converter box right below the power supply. When I removed the black 3D printed cover I didn’t see them, but I guess they are under a little cover. I will replace those as well. My guess is that one of these fuses is my problem. As soon as I get all fuses replaced I will report back.

Hope it works out for you.

I did a little more probing with the multimeter. I decided to check the power supply right behind the power plug (past the two little fuses inside the power plug) and I had just over 120 volts coming in. So the fuses on the power plug are not the problem. I did check the fuses resistance anyways and they checked out fine. I then moved over a couple inches to the power out wires that go to the machine and I got nothing. So I definately have power going into the converter box but nothing coming out. I also found the tiny fuses on the Rambo at a local hobby supply shop so I replaced those just in case, but it didin’t help. I couldn’t wait for the ones I ordered online to be delivered. The shiping email said I wouldn’t have them until the end of next week. I just can’t wait that long. So I am now confident that my 120v to 24v converter box is bad. I have not taken it apart to check for any internal fuses, but if they were in there I am assuming Brent would have mentioned that. The only fuse I can see by looking into the vents is soldered directly to the board and not really replaceable. Any idea on what to do next?

Thanks for the update! We can get you a replacement power supply, contact us at support@lulzbot.com with your order information, your desired shipping address and the information you shared here (if you don’t mind) and we can open a return for you.


Thanks. I will send you guys a message on my lunch break.

Edit: message sent

A new converter box is on the way. Unfortunately my warranty was one month out so I had to buy it. That sucked! At least I will have the part soon and can get my machine up and running again.

I got the new converter box installed night before last and the machine came right back on. I have had 4 successful prints since the install. Brent from Lulzbot said he had not heard of the 24v converter box failing on anyone. I guess I got to be the first. I plan to take apart the old one and track down the failure point some time over the next couple days. I don’t want this issue to happen again. If I find anything then I will let you all know. Hopefully it will be an easy fix that I can pass on to you all. If I can fix it then I now have a backup if the 2nd one fails.