[weblacky]

"Graphics out of range" has nothing to do with CRT technology. Standard SGI PROM Resolution is 1280x1024 @ 70Hz (maybe 75Hz), your LCD monitor doesn't likely understand the resolution refresh rate past 60Hz. You'll still need a Sync on Green (SOG) tolerant or compatible monitor (even though it's DB HD15 and have separate Sync pins and is a VESA standard, still outputs SOG. You'll have to deal with it.

Best LCDs for this are older Dell 2007wfp (like) and Samsung Syncmaster 15"-17" LCD s4:3 aspect. Normal VGA cable.

Don't try any weird HDMI, DVI, whatever converters. Just find a cheap 15" LCD (square 4:3 aspect), it will likely support it (check the manual of the monitor if you can, back then...they actually told you if it was SOG compliant).