Hi Kees,
I thought before it was 25 but now see the dot at a diffrent angle. The multi meter reads 02.1 without wires and with the wires attached its 02.5 .
Im a multi meter noob so I have set the diel to 200 and then the horse shoe shaped sign which I believe to be correct.
I did reply but it got removed because I referred to myself as a newbie with multimeter.
Any way yes I have checked that I first thought it said 25 when I measured with the wires. but looking at the screen from a different angle I now see the decimal place. It measures 02.5 with wires and 02.1 without on each pair.
Hey guys,
The last thing I never tried was to swap the extension cable with one from a known working motor. I swapped it out with one I made for the Z axis and it worked instantly.
The difference between these two cables is the wire I used. I ran out of my extension cables wire 22gauge. But had some wire laying around that I use for building aeroplanes (Servo wire).
Its pre twisted 3 cables so i had to split one length to get the forth cable. I have tested for continuity and that is still fine and dandy as i would expect. So my conclusion is the twisting cause some level of interference.
Or because 3 cables are twisted and one is not the 3 cable in theory could be longer then the one un twisted. Could this have cause the erratic behaviour.
The other cables I got my wife to help me braid so they are kind of twisted but not done by machine so I wonder if amount of twist has an effect on interference.
I don’t like a mystery but I feel I may never get a satisfactory answer for why this cable doesn’t work.
Working extension wire (apart from I used stranded): https://www.amazon.co.uk/TUOFENG-Wire-Solid-Different-Colored-spools/dp/B07V5FVSYL/ref=sr_1_1_sspa?dchild=1&keywords=wire+22+gauge&qid=1608383565&s=industrial&sr=1-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzMFRMOUtIRUgxSDY1JmVuY3J5cHRlZElkPUEwMjEyMTk2MjM2UTYyN1BMOFdKSSZlbmNyeXB0ZWRBZElkPUEwMjg1ODg0M0szMUJZOEhZQ0QwWiZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
non working extension wire: https://www.amazon.co.uk/OliYin-60cores-Twisted-Extended-Extension/dp/B07D33ZY74/ref=sr_1_4?dchild=1&keywords=servo+wire&qid=1608383611&s=industrial&sr=1-4
Thank you every one for all your help and time.
Like I have checked this cable so many times its colour coded, its wired correctly it has continuity. I’m blown away. Even now I’m looking at multi meter everything is fine with this extension.
Could it be shielding or the lacking of shielding?
I feel I don’t have enough electrical engineering prowess to be able to answer this my self.
As a thank you I have 6 spare Little Fuse 5a fuses for the Rambo board, if any one is in need of a couple in the uk.
Cool. Glad you fixed it.
Emi is usually from something that is sending Amps and generates milliamps. Motors are usually pretty immune, because it takes a lot of current for them to care.
That is a nice offer. As for the rest mystery solved 
kind of. and move on 
glad you got it working