I guess my quickest way forward here is to buy another 800w spindle & hook that up ...if it works, then my old spindle was faulty (which I think it is), if it still trips then I can sell it on!

Some of these water cooled spindle adverts tout themselves as 'four bearing' ...do I need this if I'm only milling pcbs & acrlyic? (in other words what does four bearings bring to the party - they're about £30 more vs the cheapest 800w water cooled spindles on Ebay)