G4 PowerBook won't boot

[CooperBox]

My son's 1.67GHz G4 15" Powerbook has all of a sudden refused to boot. No sign of life at all - with the exception of the ring around power adapter plug - which is illuminated when connected to the computer, as it should be. I've tried another power adapter just in case, but no change. Both of these power adapters are ok with another PB.
I installed an SSD to this PB last year (which was a great improvement) and everything has worked fine until today. I've checked that the single 2 GB Ram module is securely installed, removed it, cleaned and refitted. No change. I know the battery is ok - 4 leds lit during self check.
So in summary, it's refusing to boot from a known good battery, and also from a known serviceable power adapter. No chime or any sign of life from screen.
Any advise please on troubleshooting this.
Incidentally I have my own 1.67GHz G4 15" PB (a wonderfully 'clean' example purchased recently from fellow member Lastic), but at this early stage I don't plan any component transplanting from one to the other.

 

[eyoungren]

Things to try.

1. With the Mac off, remove the battery. Attempt to start the Mac.

2. PMU reset. With Mac off, remove battery, disconnect charger. Press and hold power button for five seconds. Reconnect charger and battery. Try and see if it starts.

 

[CooperBox]

Things to try.

1. With the Mac off, remove the battery. Attempt to start the Mac.

2. PMU reset. With Mac off, remove battery, disconnect charger. Press and hold power button for five seconds. Reconnect charger and battery. Try and see if it starts.

Bingo, this worked a treat! I'm sweating no more.
Many, many thanks!

Several times recently I'd removed the battery and used the PB from mains power, as I have a powerpoint alongside my favorite chair. Can this action possibly be detrimental to the power management?

 

[eyoungren]

Bingo, this worked a treat! I'm sweating no more.
Many, many thanks!

Several times recently I'd removed the battery and used the PB from mains power, as I have a powerpoint alongside my favorite chair. Can this action possibly be detrimental to the power management?

Glad it's working!

As far as detrimental, no not really. I tend to leave the battery in though if for nothing more than to occupy the hole that having it out leaves.

None of the batteries I own for my MBP or PowerBook would last beyond two minutes but I'm always using the power adapater so it's nothing I've ever bothered to replace.

 

[CooperBox]

Glad it's working!

As far as detrimental, no not really. I tend to leave the battery in though if for nothing more than to occupy the hole that having it out leaves.

None of the batteries I own for my MBP or PowerBook would last beyond two minutes but I'm always using the power adapater so it's nothing I've ever bothered to replace.

Ok thanks.