The power cable can be either 240V or 110V, but it will need either 15 or 20A depending on config AFAIK. It's only the later Onyx multi-CPU+RealityEngine that requires 240V power. Can't tell you where to get the cable, didn't even see them in Boeing when they were selling off Onyxs. If you have an Indigo/Onyx keyboard (Mini-DIN 6 but not PS/2) it's a simple plug adapter to use it in 4D/Crimson/PI machines - look at the 4D/FAQ (search for "This Old SGI") The Crimson uses the DA-15 connector rather than the early PIs DE-9, but this is the only difference. For IRIX, you'll get the best support for modern applications with IRIX 6.2, but you will need to partition/label the disk in fx on another machine or using the fx that comes with IRIX 4 or IRIX 5, as fx.IP17 is broken on IRIX 6.2, IRIX 5.3 will give you the option of running older ECOFF binaries built for IRIX 4, however, and if your Crimson has GTX graphics rather than PowerVision or RealityEngine you will need to use 5.3. Less than 96MB you'll probably get better performance from 5.3, other than that it's your call - 6.2 has the POSIX pthreads patches available and n32 binary support (and some newer freeware- 2001 was the last 6.2 build on freeware.sgi.com, and there's an offshoot of Nekoware for 6.2 (tgcware, perhaps they have some 5.3 builds available).