X axis missing steps after Y has moved a fixed amount!

[bluebirdiran]

Hi to all

I have this homemade plasma CNC that was working alright. Suddenly the x axis started to miss steps and then stopped alltogether. This now happens regularly but sometimes without stopping, only missing steps. I changed the motor, no good. I swapped over the X and Y drives but the same motor still has the problem. I changed the transistor in my buffer circuit, no good. I changed back to the motherboard LPT port instead of the auxiliary one that I had been using, no good. I installed KCAM software instead of Mach3, the same problem. I reinstalled Windows XP, no good. One consistent thing seems to happen though and that is when the y axis has moved about 25cm, the x axis starts to show this problem. Apart from calling in an exorcist, can anybody tell me what could be wrong that I haven't looked into yet.
Motors are 18 kg.cm chinese
Drives are chinese

Thanks guys
Bluebird

[Hood]

Checked your cabling on that axis? Sounds like something may be loose or even a broken conductor in one of the cables which lets it works a bit. That may be consistent with the Y distance depending on the setup of the machine as possibly the Y moving is flexing the X axis wiring?
Hood

[bluebirdiran]

Thanks Hood, You were spot on. Although I had suspected this as well but could never bring myself to believe that a three strand cable of 1mm dia. each could ever do that to me. The chances were infinitesimal. But it was that. Thank you very much.
Cheers Bluebird

[Hood]

Good you found it

Hood

[Hood]

Oh and BTW solid core cables will snap very easily with flexing, much better to have the cores made of lots of small strands.
Hood