I have a Powerbook G4 Titanium 500 MHz computer. It will not do anything. Will not turn on... will not charge battery. When power adapter is inserted, the ring is red (orange).

I have tried booting it with the battery installed and without the battery installed. It does nothing.

I have also tried resetting the PMU by pressing the reset button while the battery and power cord are removed from the computer. This did not help either.

I tried resetting the PMU with power sources.... again nothing.

I tried starting the holding the power button and Command-Apple-P-R.... still nothing.

Any suggestions???

P.S. my battery has no charge...

Is there a way to test whether the PMU or the mainboard are bad??

Could it be the backup PRAM battery??? note: the computer has sat on a shelf for 7 or 8 months untouched.... (it does not belong to me... I would have been using it).

From what you describe, you're looking at either a bad logic board or PMU board. Most likely the logic board is the culprit. The only way to test is to change out the parts.

-Bradley
POWERBOOKMEDIC.COM