I seem to remember some suggestion that the fans are powered directly 
off the 3-phase supply, but I could be wrong. There's almost certainly
some kind of interlock to prevent the rest of the machine from powering
up if there's no airflow -- certainly the 750 has such a safety feature.

James

markus wrote:
> 
> > > I've been trying to get console on my VAX8350 to no avail *sigh* I've
> been
> > > made aware that I may potentially need some sort of console boot media
> for
> > > the RX50 drive on it. I've got the proper cabling and terminal/settings
> etc
> > > etc, but still do not get a prompt. There is power going into the main
> bus
> > > as there are three lights that light up inside the main box but none of
> the
> > > modules power up nor do the fans. I believe you must get console and
> then
> > > type in either 'boot' or 'start' to give juice to the other components.
> If
> > > anybody can give a general description of the boot process of one of
> these
> > > machines, in addition to any pointers it would be appreciated.
> > >
> > Well, when you apply power to your machine, the fans should start
> > immediately and you shall get a '>>>' on your master console.
> > If you do not; then you have a hardware problem somewhere.
> 
> NOTE: I am plugging the main unit into the wall directly using its standard
> 115V plug, not into the phase3 supply and then into the wall. should the
> fans and modules operate under these circumstances?