Thank you tons for this post. I was able to revive our porsche design lacie hard drive by this post, and move all of its contents onto a usb eternal hard drive of todays standards.

Pins 3&4 are ground, Pin 1=12V, and Pin 2=5V. I doubly verified by continuity testing each pin to the red, yellow and black wires that power the drive. The standard is maintained where Black is Ground, Red is 5V and Yellow is 12V.

It may also prove useful to others that this is the correct pinout for the
LaCie Mini Hard Drive (FW 400 only)
4-Minipin
708014