i have been working on a Powerbook 150 lately.
Had the same symptoms a powerbook 140 have when the display capacitors are bad, showing only a blue-grey screen.
The startup sound was missing also, but the hard drive seemed to be working.
Removing the display (Casio unit and not Sharp) proved me wrong, capacitors were ok with no leaking at all.
i had a hunch concerning the missing sound.
The Pram battery was nearby the speaker, and leaking...

Indeed, three traces were broken underneath, two for the speaker, and one coming from the inverter board (i replaced the only capacitor at the same time)
Once all patched, i got a working unit again

Had the same symptoms a powerbook 140 have when the display capacitors are bad, showing only a blue-grey screen.
The startup sound was missing also, but the hard drive seemed to be working.
Removing the display (Casio unit and not Sharp) proved me wrong, capacitors were ok with no leaking at all.
i had a hunch concerning the missing sound.
The Pram battery was nearby the speaker, and leaking...

Indeed, three traces were broken underneath, two for the speaker, and one coming from the inverter board (i replaced the only capacitor at the same time)
Once all patched, i got a working unit again



