Hello knowledgable colleagues..... I just discovered the "Driven Pulley" on my 600m is cracked. It broke the belt and the pulley mandrel is actually a little off center now. Some questions........ 1.) Where am I gonna find a pulley? 2.) Why did this pulley crack? 3.) Will a 610 and 600 be the same? 4.) Where will I find the Serial Number on this unit? My dealer asked for it Thanks a pile....... Khal [email protected]