In some PPC Macs where there is either a capacitor or a clock battery on
the logic board, the replacement of one no longer holding power is one
way to troubleshoot. An iFixit guide can tell you if the unit you have has
a PRAM or clock battery, or capacitor, and if either one, the location so
as to replace it. I'd suspect there may be more than a few things wrong.
You may be able to contact AppleCare or sales support by phone and
ask for an OS X system specialist or someone who can help you get
a replacement OS X install disc for your PPC PowerBook G4; they did
have some white-label replacement (not to be re-sold + not retail) for
a relatively low cost of about $18 each and not all persons who sought
these white label (Tiger 10.4 and also Leopard 10.5) full install DVDs
were able to get them from AppleCare or sales support. This was not
through the regular retail channel, and these are generic white label
replacement, not specific to one model, and usually for PowerPC Mac.
So that may be something to inquire about; be sure to find and share
the serial number with them when you call, to help clarify what you have.
They no longer offer original Mac install-restore part numbered DVDs.
But Leopard 10.5 (PPC) on DVD is what you need, then download the
Combo update 10.5.8 from the running OS X. You could attempt to boot
the computer with such a DVD, to help try & troubleshoot.
Who ever took out the hard disk drive may have done some damage.
There may be a few things wrong in the computer, and if it won't charge
the parts involved could be: AC Adapter, Battery, DC-in Board, logicboard.
A few others could be working together to keep the PowerBook in a coma.
Hard to say exactly. Helps to have some tools to troubleshoot... đ