The fact that there are 2 very difrerent types of fan would possibly explain why some people have no problems with this arrangement of units in the rack. It's the one I mentioned, I think It's a normal shaded-pole motor. If you look at the stack of laminations (the 'block of iron' you mention), you'll see 2 thick copper loops round part of the pole piexces near the rotor. These act as short-circuited secondary windings (with the normal coil acting as a primary), and cause a phase shift to the change in magentic fluc on that part of the pole piece. The result is a rotating magnetic field that causes the rotor to spin. Actually, the 'muffin fan' motor works in much the same way, but it's a 'Papst motor' with the satore in the middle and a cup-shaped rotor around it (I asusme you've taken a fan apart sometime...), One of the results of this is a much lower stray external field (it's screend by the rotor). I'd try replacing it with a muffin fan. I am pretty sure it's just a normal 115V 60Hz one in your case. I can't remember if 230V RX02s use a 115V or 230V fan, I would have to check the printset, but that doesn't apply to you anyway. -tony