Hi irving2008,

Looks like I did not create an ISO. Am reading about those so I can try again.

John,
Downloaded the analyser and tried it briefly. The graphical output showed some red pulses, but they were all in a block. I need to play with that a bit more, but my Wife is getting upset with the amount of hours (days!) I'm putting into this.

Started again with a clean install this morning, following the Mach3 windows optimisation steps. Disabled everything on the list (sound, gone back to classic, switched off auto updates etc.etc.). Switched to 'standard PC' in hardware.
Still glitches.

In BIOS have disabled: game port, midi port, AC97 audio controller, onboard lan (nvidia), onboard lan (3com) 1394, serial port1, serial port2
Parallel port is set to: 378/IRQ7
Still glitches.

Then went through all the parallel port options in BIOS: ECP+EPP DMA3, EPP, ECP DMA1, ECP DMA3, SPP, ECP+EPP.
Still glitches.

Then in Mach3 traversed at various speeds (since I noticed that 1500mm/min did not glitch since this fresh install). Noticed that: 50,300,500,700 mm/min all glitched. 1200 mm/minute occasionally glitched. 1500mm/min never glitches, nor does 2500mm/min. 3500mm/minute makes the motor sound unhappy (but not glitching). Cutting at 1500mm/minute is not possible, so this is not a solution but may point to the answer.

I hooked up the scope to the system3 boards whilst it was running, onto pin3 and earth. At 1500mm/min (when there is no glitching), the scope does not give a steady spacing between pulses and is very inconsistant. I can no longer rely on the scope and need to use the motors as a glitch guide.

I'm beginning to think there is a fault with the MB (or parallel port). Even used on ebay this spec of board (ASUS A7N8X) still is quite expensive. What MB are people successfully using Mach3 with?

Thanks for your patience !!
Barry