Power pulse issue

I have an issue I’ve been dealing with for weeks and cannot get figured out. I’ve emailed support and they have responded, but I’m lucky if I get one email response a day and now we are headed into the weekend, so I’m hoping to get some additional help here.

My problem is missed steps, which I assume is being caused by a wierd power pulse im getting…heavy on the assumption here.

I have triple checked the following:

Belts are equally tight
Set screws are tight
Machine squared and trammed
All machine bolts are tight
Table, router and vac house are all grounded
Router and machine both run on their own separate circuits and are plugged into EMI power surge protectors.

I discovered the power pulse when I left the machine on while I worked on a file. It randomely started sounding like it was rapidly powering on and off. The light on the power switch would flicker as well. The blue light on the control board would stay lit and would not flicker.

I checked all the wiring for a loose connection and everything is tight. I went through each wire individually thinking if I moved it around, I would be able to duplicate the sound from a possible short but no dice.

I feel like the randomness of the pulse is what is contributing to the missed steps on a job. I ran a 3.5 hour job on a flag inlay and it ran flawlessly the entire time. Set up a new job for the pocket and it carved random pieces all wonky. See the stars in the pic. Some stars were perfect. One was all jacked. The others missed steps enough to cause a rounded i side point.

Has anyone ever had this issue? Im considering a power conditioner or UPS, but if this is a machine or motor issue, id rather have cardibe3d replace it before i spend a bunch more money.

Everyone raves about their customer service, but I have not had much luck so far. I get one response a day via email and have to wait another 24 hours to hear from them. The first person I was working with disappeared and now another one has taken his place. There’s only one day a week I can do a video chat, due to my work schedule, and I have that scheduled for next week.

Their last request was to “Send a video of the problem”

The problem with that is the power pulse is so random and so short, it’s impossible to get a video.

Any thoughts??

What else is on the circuit?

If you get a UPS, make sure that it is designed for the load of motors — there are electrical implications apparently (see previous discussions here).

Every outlet in my garage/shop is on the same breaker. When this issue started, I thought it was an EMI issue, so I switched outlets and started running the machine on an extension cord to the outlet on my front porch. It’s progressively gotten worse no matter what outlet I use. I have a refrigerator and a chest freezer on their own outlet. Other than that, everything else has it’s own outlet and nothing else runs at the same time as I’m running a job on the cnc.

Part of my weekend list is to grab an outlet tester and check them all for issues


If a circuit is running at or near max, when a load changes on that circuit it may cause an issue. I liken this to seeing lights dip when the freezer or what ever clicks on. Don’t know your building, try and get a new circuit run to the machine.

Good luck

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Your description doesn’t intuitively sound like a power fluctuation, more likely a machine issue - but as you say ‘heavy on the assumption here’. Intermittent faults are the worst - the issue needs to reveal itself whilst you are able to interact and discover root cause…

  • Does any other equipment suffer at all, or show the same fluctuations?
  • Stepper motors sounding like they are disengaging/engaging rapidly might indicate a driver IC issue on the control board (practically that means a replacement board). It might also indicate an intermittent connection somewhere in the wiring - a weak connector/connection, or a partially broken wire
  • A common factor may be the 24v power brick, is there any chance of trying a replacement?
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You’ve never said what machine you have or how new it is, but the load from the machine is really fairly constant; not intermittent.

Sounds like the switching power supply to me. (UPS isn’t going to change that, but you need one anyway. Maybe this would never have happened if you were running on a UPS???)

If it was your local AC power, then you would have seen some other light in your shop flicker at the same time. You didn’t mention that happening, so I’m thinking that the power fluctuation is local to your machine which means it is happening in the DC part of the power supply; probably a capacitor going bad. That would/could be intermittent.

The first thing (with these symptoms showing) C3D should have done is replace the power supply.

Your ticket is open and active in our system, but is assigned to a technician who usually works Mon–Fri — I’ve linked this discussion there, and we’ll do our best to have someone check in on this and get this resolved as quickly as we can.

Thank you Will. I appreciate the effort.

It’s a Shapeoko 4 XXL less than 6 months old. I live in a little duplex apartment with a 2 car garage that I use as my shop. There are usually just lights on when I’m experiencing it, and they do not flicker. I will occasionally have a breaker trip in the garage when I’m running multiple other pieces of equipment to do other projects.

The sound is for sure the stepper motors rapidly engaging and disengaging. It’s not quite as loud as the sound it makes when I first turn it on.

No other equipment shows this power pulse issue, that I can tell. If I have too many machines on at the same time, I will trip the breaker, but that’s more of a circuit load issue and understandable. When I’m using the cnc, I do not run any other machines, other than my little shop vac.

As far as I can see, all the connections are good. No clue how I would find a broken wire though.

I don’t have another power brick to test and I doubt I’ll find one compatible with the female connection going to the control board.

I would think like previous members, a problem with the 24V power supply. If this is not the case, may be something creating a very quick short. Does it happens when the CNC is just idle not moving?

Happens both idle and while carving. I can’t actually hear it while carving, but I’ve seen it pause and freak out, before continuing on again. When it continues, it has lost steps and ruined the job.

So I just turned the machine on and went to look at the power box to see what I needed. It immediately started pulsing again and the green led light on the power box would flicker and dim while it was ocurring.

If it wasn’t under warranty, then I’d tell you what I’d do with it. :smiley:

Trust me, I know. This machine has been one problem after another since the day I bought it. The router is also already toast. They haven’t even addressed that issue yet.

I’m really hoping it’s just this power box. Ridiculous that a machine this expensive has this issue, but it’s easy enough to fix and keep an eye on.

You have to eliminate between the CNC and the power supply, either you try another power supply, it can be a regulated ajustable supply or a similar specs power supply, or you put some can of load on the supply to see if the problem still persist, it can be a power resistor, two incandescent car bulbs in series or another equipment working on 24VDC with a curent lower than the spec of the power supply.

Since it is still under warranty and depending on your electrical knowledge/skills, my previous tests suggestions might be not appropriate.

If the router is bad, we’ll send a replacement, just send us a photo of the nameplate/badge and we’ll get this taken care of.

Thanks Will. I was going to bring it up again when I spoke to them on Monday, so I don’t end up with multiple open support tickets.

I’m not smart enough, but just for s&g’s how about powering down completely for 24 hrs. Unplug from the wall everything that is connected to the machine and then see if the problem repeats. Just make sure this test is on scrap.