Where is a decoder for diagnostic LED pattern?

iMac G5 20 22 Model A1145

I am going to start working on my dead iMac G5 with isight, but with all the mentions in these threads of the diagnostic LED functions. I've yet to find a link or list of what they mean.

After a brief power outage, my old iMac probably was fried in the surge when power came back, so I suspect all I need to know is the one for a dead power supply. But still.

This is a follow up question to the information you kindly provided above: The 1st LED stays lit when I plug it in, but when I push the power button, LED 2 flickers on for less than a second and then goes off again. The iMac stays black.

I have tried to reset the SMU by plugging it in while holding the power button, but nothing has changed.

The computer became bricked after a brief power outage (and was the only machine in the house not on a power strip).

Any ideas?