Voltage Present

try disconnecting the “powered” usb hub and see if it is still present.

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After much unpluging and pluging including swapping cables
The only way to reove the voltage is to remove the Y2 cable from the machine (y right side motor)
The socket in the end of the right rail has 4 connectors in it the top right one has continuity with the rails so i am assuming a fault in the socket the internal cable or the motor?

Any thoughts?

Pretty sure the Y socket should not have continuity with the rail!

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That was my thought, not sure if Onefinity monitor the forum or weather to drop the a line

Hey Jim, hey @CSM Darren,

yes, I agree,


you did not answer my question:

If, with multimeter connected between the case of the Onefinity Controller and the rails of the machine, and you see the 17 Volts, and then you make a an electrical connection between between the case of the Onefinity Controller and the rails of the machine (a short, with wire) for a few seconds and then remove it again, then do the 17 volts which collapsed and disappeared then (and the question is): Are the 17 Volts then still there again afterwards? Immediately?

Hi sorry
I connected a wire from the machine to a know good earth point when i swicted the machine on a Y motor fault appeared on the screen and i could reset the stop or cancel the fault i then powered down before removing the temp ground wire
I am convinced that the fault is in the right Y rail internal cable or motor or socket which fills me with dread as i assume its a machine strip down job

Yes I agree. There should not be a connection between a motor driving conductor and the rail.

And without this fault, you should be able to ground your machine. In this faulty state grounding it renders the machine unusable.

you may proceed with error diagnosis by disconnecting the stepper, but I’m sure it’s the cable or the connector of the cable.

As I think I already stated earlier, these tin-plated Molex/Amphenol Connectors used on the Onefinity are the first thing I will throw away when I will receive the machine and replace them with decent gold-plated industry standard circular connectors.

These tin-plated Molex connectors have been a disease in computers since decades, can’t say how many data loss they caused, and they’re still there, e.g. as ATX power supply connector. The problems that this causes, of which I can report from many years of experience, are in my opinion not at all appropriate to the requirements for the reliability of computers. It’s just money-saving on the part of the manufacturer.

Tin-plated contacts are tolerable if they are plugged together exactly once. Disconnecting and reconnecting them causes problems. Tin is not very hard and the problem is that the wear and tear that occurs with every mating cycle leads in the long term to the contact coating chafing through, exposing the copper alloy underneath, which is even more susceptible to corrosion. And even without touching, the tin itself oxidates with time (and tin oxide is no more a conductor).

I’ve been following this forum since March, and the problems with the cables and connectors keep coming up from time to time. But at least Onefinity seems to have very good support!

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I bet one of the lines got pinched inside the steel tube, or the plug hidden in the middle of the tube is the cause. I replaced all those wires with a continuous run of IGUS CF6 shielded cable.


All sorted there was a short between the right Y rail motor cable and the machine body Replacement cable on its way from Onefinity

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Hey Darren, hey all,

I understand.

The day you reported this, a new video popped up:

Support : How to Access the inner tube motor wire


Hey Warren,

IGUS chainflex CF6, that seems to be an excellent choice.

Did you replace the connectors too?

I bought LAPP ÖLFLEX® CLASSIC FD 810 CY for the spindle power. It is highly flexible, shielded, has double PVC inner and outer sheath and is specially designed for use in Power Chains.

I replaced end to end in a continuous run. My weak link is my ability to assemble the small plug that goes into the controller.

I found that molex sells the plugs preassembled with a length of wire attached. I think I will redo my ends by splicing those onto my cables. A machine made connector has to be better than any I will ever create. My problem has been in getting the pins to properly seat in the shell. I’ve gotten quite good at the crimp pins, but then invariably one or more pins don’t fully lock in. I epoxied the wires in, but the premade should be better.

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Where did you attached the ground too? Did you take a picture of the short?

How do you attach to the controller box? Must have to open it and modify the female plug socket?

Here is how I set mine up. I grounded the metal piece the controller was bolted too. I also grounded the frame and most important the dust collection. See photos in link below. Opening and modifying the machine seems like a quick way to void your warranty. :grimacing:


Sorry I so realize your post is quite old, never the less I wanted to reply anyway being I have had this same problem my self and seems as though most everyone is asking the same question and or the same problem and not going about solving it. So it seems I may have come to a solution in my case anyway and hope this works for you if you haven’t already found one.

This is assuming you may have a dust boot!! So what I have done is taken and connected from the dust boot itself and then connected a small gauge electrical wire from the dust boot to a nut and bolt located elsewhere on the boot assembly.

I did not want to ground to the frame itself as I felt it could “possibly” make things worse rather than fix it. Secondly most people are trying to ground they PVC tubing which CANNOT be grounded! Period! You cannot ground non metal/ conductive surfaces and even doing so requires an immense work to “try” to do so.

Here is a photo of what ive done. I hope this helps! Since doing this I have noticed NO sparks/ conductivity at all!

(having trouble uploading the images so I will try to do so in a separate reply)


There was a longer write-up in another thread regarding the post above, which shows an alleged continuity pathway from aluminum > acrylic > bonding wire > PVC jacket on a flex hose. I’m linking them together so that they’re not addressed separately:

Yes please link them if you can. Thanks