Powerbook Sleep light Stays Solid During Use

Hi

I just bought a used Powerbook G4 for NZ$400 so about $300US and everything is perfect on it except one thing i cant get my head around, the sleep light on the front stays on even when the computer is being used. It pulsates when it goes to sleep but when it is being used normally it just stays a solid glow.

Any Ideas?
Thanks

Have u tried resetting the PMU? Resetting PowerBook and iBook Power Management Unit (PMU)

Yea I tried that and it still did it and then for no apparent reason an hour after this the light has turned off, will see if it comes back in the next few hours

Arrrg its back again, its so annoyingly confusing!