Hi John S..

Just checked and only the X axis had the pulse width set to 0, and it was running fine, have set it to 5 now.. z and y were already set at 5, vaguely remember doing this way back when..

Just fed in the code f25 z100 and it moved the z axis fine, for about 30 secs, then started juddering, faster and faster until it was juddering all the time.. Did the same with the y axis, and this took about 45 secs to start juddering.. Both the z and y are running off the system 3 board drivers and the 24v power supply, which is being fed through the board.. 2.30am now so starting to see double.. Will start some more hair pulling in the morning...

Steve...