PowerBook gave up the ghost

Well this morning I finished manually upgrading my PowerBook G4 to Jessie. I verified all was good then I rebooted. The boot loaded showed everything was fine, then black screen...nothing. Hmm so I thought maybe I did something wrong? So I turned it off and tried to reboot but it would not even go to POST..no apple chime. So I unplugged waited for some time and tried again...still no chime. I fear that my faithful PowerBook has breathed its last...