Help diagnosing a non-working powerbook...

hi folks, im hoping you may be able to help me bring a g4 powerbook(aluminum) back to life. i recently purchased this as semi-working, and am attempting to fix. the lowdown:

-i installed a brand new WD hard drive. NO OS installed on it.
-reseated the cd/dvd drive. seems to work properly, in that it accepts a disc.
-reseated the internal battery.
-battery doesnt hold charge at all, but power supply lights up, and seems to work properly.

here's the problem: it doesnt boot at ALL. upon powering, the drive spins, but i get no screen images at all. also, it will not do the "auto power down" thing if if hold the power button down; i need to unplug the PSU to power it down(i can hear the HD spinning, or at least the comp doing something)have tried:

-booting in safe mode(didnt expect this to work without a HD w/ an OS on it, but still...)
-booting from disc.
-booting from disc with all combinations of the internal HD and battery disconnected.

any ideas how to further diagnose? i was told that it definitely did not have any water damage at a point. thanks for the help.

Rjd2,

I am probably rehashing what you have already tried .. but

Have you tried re-set
cant remember if there is a reset button on these for the pmu but
the key sequence might work.

PMU, hold down Shift,Control,Option, and the Power button at the same time
PRAM, hold Apple, Option,P, and R at the same time right after powering
on the system .. then continue to hold those keys after the cd seems to
reset .. if you get the apple ding .. continue to hold that for 2 more dings

this will ensure the pram is reset.

Other than that .. with out tearing back in to it .. not sure what else could
be going on ... you have checked the memory and reseated.

what was it doing before you installed the HDD and reseated the cd/dvd?

Hope this helps

thanks alot for the help. when i received it, i tried to boot it; here's what i got:

-1/2 of the boot up "chime". it then immediately shut down.

i have yet to actually verify that the screen works properly, as i havent seen an image yet, but i am led to believe that its probably ok, because i can CONFIRM that there are much bigger problems w/ the comp.

so i have now reset the PRAM and the PMU, at least in theory, but i am getting the same thing. upon booting, the cd/dvd disc drive spins for 15 seconds or so very fast, then slows down. NOTHING on screen. no sound. the comp also will NOT do a forced shut down via power button. same if i hold C to boot off of disc, or if i dont.

this leads me to believe that something is freezing up in the process of startup-any more ideas? i have other macs in my house, so in theory, i could try to boot from an external drive via firewire, but they both have critical info on them and are primary work comps, so if there is the chance this woould affect them adversely, id rather not.

thanks much for all the help.

Do you have any confirmation that the mobo isn't bad? I had an ibook that lost the mobo and the hard disk and DVD drive would spin up, even the power management seemed to be fine but the mobo was dead. If you think the mobo is good I would try installing an os on the HD through another machine and putting it in and seeing if that happens, but its a long shot. Another harmless thing you could try was getting the thing to boot in target disk mode by using firewire to attach to another computer, once again a long shot. I hope I am wrong, but i would diagnose this as a failing mobo.

i dont know if logic board is bad. i just broke down and ordered one that i can return; looks like this is going to be essentially a complete rebuild, which is fine, as it still isnt looking to be too expensive....

What about Target mode? will it boot into that - hold down T after power button. If it is go you will see a firewire symbol on screen.