Starturn 4 - Differences and basic tests

[Andy B]

I've seen advertised a Starturn 4 for retrofit (like David Murray did). The machine unfortunately isn't a 'take it away from our dusty cupboard', as some others have managed to obtain! I believe it is a stock machine, without it's BBC/Acorn to control it.
So before I part with beer tokens, I would like to check what to expect and what is or isn't working. I'm hoping some folk might be able to answer the following:

Is there any difference between the (earlier?) ones painted red and the ones painted blue? (...apart from the colour...!)
If it is just powered up, but with no computer attached, should it be possible to start the spindle and vary the speed ?
Is there an easy way to check if the stepper motors and drivers are working (don't know which drivers are fitted to check in the driver manual if there is any sort of 'test' mode/function).

Thanks in advance for any help.
Andy

P.S. Don't suppose any one knows of a 'dusty cupboard' machine that wants a new home?