Lulzbot power supply problem

I hooked up the 12v 30a ps and set the adjustment screw so it was reading 12v a couple weeks ago. I set up my ramps 1.4, tested the motors, took another voltage reading and it was now reading 22v-23v (ish). I then tried turning the adjustment screw down, but it would only go as low as 21.

Any idea what may be happening here?

Please help! So close to running my first print, but don’t want to proceed until I figure this out.


I’ve never heard of a power supply just randomly changing outputs like this before. Are you sure you’ve got the 12v one? It should say on the front of the supply – something like “DC OUTPUT +fooV barA”.

Where was the power supply purchased from? If it is indeed a 12v power supply it certainly should not be outputting close to 24v.

Thanks. Yes at least that’s what it says 12v. (See pic)

Tested my multimeter in the wall and it’s giving me 114 and on a 9v batt it reads just under 9v. So it doesn’t seem like the multimeter.

Im checking the psu right from the terminals and still getting 21v. I’m sure I had originally set it to 12v with the adj screw a couple of weeks ago.

Orias, from lulzbot. The guys here are looking into it. The crazy thing is, I swear it was originally outputting 12v. Maybe I had just stayed up too late that it even possible for a PSU to just switch?

Would you mind sending in the picture, your order number and preferred contact information/shipping info to We’ll then be able to see what we can do. This is a unique occurance. We haven’t seen a 12v power supply upgrade itself to a 24v power supply :smiley:

Done. I sent an email to help desk. Just took these pics of me testing it now and it showing 21.1v.


You need to set your multimeter to DC volts to get a good reading. That’s 4 clicks ccw from the setting in the picture you posted.

cfry9999, this can’t happen. When I say this can’t happen, I mean usually power supplies would burn rather than outputting such a weird voltage. From the picture, you’ve shown, it seems like the multimeter is set to read AC voltages and not DC voltage. Please revisit the whole procedure with configuration of multimeter.