[G4] MDD 1.25 ghz ON-OFF Switch Not Working

[jonny]

Hello List.

I have a G4 MDD 1.25ghz with an Apple Studio monitor.

I use the lighted "button" on the lower right of the bezel on the 
monitor to Start Up.

But I don't seem able to turn things on using the button on the G4. 
I replaced the button on the G4, but it exhibits the same behavior. 
I can do a crash shutdown with the G4 button, so it seems to work, 
just not for machine startup.

Any idea what might be going on?

A way to test the on/off button on the G4 without removing it?

Thank you.

jonny