The G540 will come out of fault without motors attached. Do this:
1) Make sure you have your parallel port set to 'EPP' in bios.
2) Make sure you have DISABLE jumpered to GND (term 10 to term 12).
3) Download and install the Mach3 config file 'G540.xml' from
www.geckodrive.com.
4) If you don't want Mach3 charge pump, open the G540 and change the black switch position.
You will get the green LED then.
Mariss