Freezing, blank display and sometimes downright rude

Question

I have a powerbook G4 400 titanium that is acting very rude to me.
I can start it up, and it will get past the Apple icon and go to a blue screen and just hang there, frozen.
To troubleshoot, I've put the original disc inside, and conveniently when I reboot, the display doesn't work. I've tried resetting the pram, pushing "reset", and even holding the option key and getting both the internal hard drive and the disc to mount -- only for it to freeze. I've also tried starting it up in target disk mode by holding "T" only for it to have a blank screen and not mount on the other computer.
I've taken off the back case and checked connections, I've taken off the keyboard and given it my blessings. So, any thoughts? While I'm not willing to buy a new logic board, I don't mind buying a new hard drive if it means getting it working again.
If this is scrap, can someone point me in the direction to take the computer apart and sell it for parts?
Thanks.

Answer 1

Hi, Tim. (Icall_youTim, too.) Since there is clearly a hardware problem, and scrapping the computer is a distinct possibility, you might as well test the hard drive in an external FireWire enclosure with another Mac and see whether it's in good order. The drive will be useful with your next computer if it is, and this will give you a chance to copy any un-backed-up data that may be on it. The enclosure will also be money well spent for future use. From your description, it seems unlikely to me that the hard drive is your problem.
If the drive is OK, but you still can't start the Powerbook even from its original installer CD or DVD after putting the drive back inside, there isn't much additional testing you can really do. If you have your original Apple Hardware Test CD, boot to that (if you can) and run all the tests. You may want to try removing and reseating the RAM module(s): the PB was probably shipped with one installed, but you may have added another. They can work loose over time; they can also go bad. If you have two, try starting up with just one in place, then swap it for the other and test again, to see whether either is bad. Test each module in each RAM slot, one at a time.
Take the bottom panel off the PB and tighten up all the screws you can see inside. (Be sure to use the correct screwdrivers.) Disconnect and reconnect the optical drive's flex cable connection to the logic board, and all other connections you can see.
Complete, illustrated take-apart instructions are here. But if you decide to scrap the Tibook, you aren't going to know which parts are still working and which aren't, so you might be wisest to keep the hard drive, dispose of the rest "as is" for parts, and let the buyer be responsible for dismantling it and testing them all.