I have found the controller schematics here: http://www.cnc-router-store.com/wp-c...trolhy_eng.pdf

The voltages all seem good at the 5V 12V +37V outputs, though the 37V is reading 33.5V

What I have discovered is if I shake the PC end of the PP cable in the air, some of the axis move. When plugged into the computer (off & on) the motors are squealing and the controller relays for the spindle & coolant are buzzing, sometimes. When I remove the jumper wire from the controller back to the relays on the power board they stop okay so seem to be getting a pulsing signal from the computer end. When the PP cable is disconnected from the computer the motors are fine.

I delved into the PC and I couldn't find the PP card in the device manager and pulling it out & replacing it with a boot in between, it's not recognising it. So I plugged into the onboard PP and changed the port address and the motors at least appeared to be responding to the jog controls, though not moving (pitch can in the sound). The sleep function appears to be working too.

I swapped over to my spare pc which only has an onboard PP and I could get the axes to move roughly in the right direction, but with lots of noise & judder. They motors still squeal when stationary whether or not the PC is powered up.

I have just ordered a new 25pin card & cable as a starting point. Does this sound like an issue with the PC now or do you still think that it could be controller related. I have checked for anything that could short out the control boards and all look clear. I gave it a light blast with the airline too.