My G4 also had trouble turning On - it would light up when I pressed the button, but died as soon as I let up. I chased for a while, then I found a web posting & wiggled the connector on the back side of the switch; it's started reliably since, but now I put it to sleep most times! Peter J. Carian Sr Engineering Specialist Electronics Systems Division The Aerospace Corporation 310-336-8215 Page: 800-985-8308