Probably because the PSU is connected to the base, and not the CD section.
Don't know if the Philips and kodak branded units were the same (i Think the Power CD was the only to supply SCSI connection)
Edit from what i have found, the Power CD is the only to supply SCSI, all units are powered by the base
The previous owner has collected a huge haul of Apple stuff, apparently huge enough for a lifetime (among it... 5 Power CD's , several Quicktake units, Apple II's ans III's, probably the full range of Compact units, LC's, Powermacs... 5 Lisa's and 4 TAM's)
Everything collected from a former Apple retailler.
:-x