What could be broken?
I need to have a diagnostic advice about my PowerBook 12" G4 1GHz that doesn't turn on anymore or better it goes on without screen, without harddisk noise startup. The only signs that make me think that is on are the light on the keyboard when I click on the Shift key or when I click on F5. Then to turn off I have to put out the power plug and the battery. When I put the plug in again with the battery the light on the plug changes from green light to orange for a while, then green again. The led on the knob to open the PowerBook doesn't light on. It gives only a light noise (zzzzz) when I turn on the computer. Which part do you think it is broken? If it is the DC-DC card it is more different than the motherboard!
I tried PMU and RAM out (as suggested): all remains the same. Tried to use 2 method with CD (also suggested): nothing. Before ordering DC-DC card, to be sure that isn't the motherboard could I do something more? Thanks to all!