My old PowerBook G4 with early OSX suddenly won't start up. No startup noises, etc.

I cannot start my old powerbook g4. It makes no sounds - drive, etc. It was working fine one day, then I left it dormant/off for about a week, but plugged in to transformer to keep it "alive". Upon trying to start up again, nothing.

The battery test button initiates the first light blinking rapidly for a few seconds, second light barely visible - no other lights flash. Power cabe and transformer are delivering yellow-green glow when plugged into the mac.

Battery replacement?

Power transformer ?