Notes.
1) Notebook detects an external FDD (and swithes LPT mode) by pulling some VCC or GND pins together.
2) Most desktop FDDs requires no +12, but eats bigger current so it's better to take VCC+5 from more powerful HDD/CD power cable.
3) See note about Pin 11 in Standart Shugart-26 Notebook FDD description.
4) Without pin 13, the entire system works well.
So, a common desktop FDD can be used for Extensa 600/600CD pretty well.