I found out ours also have a oscilloscope build it, they double checked it and made all axis 10% "stiffer" to prevent possible back-lash - but it did not make any difference at all:/ They might have figured out why the spindle only starts up 75% of the time, say it might be a wiring problem, so will re-wire it. Going to reinforce the Z with a thinker back plate if the problem is coming from that side and then retest again on Monday:)