Is my iMac dead?

iMac G4 17 800 MHzEMC1936

Hi I've got an iMac G4 17" it's been unplugged for a year. I'm trying to get it running again but now it won't do a thing.

I've had the lead checked and that's ok, opened it up and reset the PMU, replaced the battery (and reset the PMU again), but each time no joy and absolutely no response.

Does this mean the power unit needs replacing or the logic board ? Or could it be something much simpler, there's never been any hint of anything wrong with the computer before.

Considering binning it once I've taken out the hard drive.

Thanks.