G4 Quicksilver startup problems

Hi all,

My early 2001 Quicksilver has been running normally over the past few months after I replaced the PRAM-battery, but suddenly refuses to startup again.

When the power button is pressed, fans start running and it seems starting up, but some 10 seconds later, it shuts down, as I posted before in this thread: https://discussions.apple.com/thread/250863609

Thyere' s a red light on. Any suggestions?

Here' s a picture:

Thanks,

Peter