PowerBook G4 does not see optical drive in System Profiler

Question

I have a very strange situation in a powerbook G4 (1.67ghz, hi-res 15" screen).
I bought the laptop non-working, installed a new power board (plug on old one was fried!) Installed a 250gb HD which I had installed OSX on in another G4 laptop, and it booted up fine, or so I thought.
When I put in my Leopard install DVD to install over the existing 10.4 Tiger, the disc spun up, but would not mount - would not eject - and when I checked the System Profiler the superdrive was not recognized by the powerbook as being present on the ATA bus. The hard drive, of course, was seen on the ATA bus.
I thought the superdrive was bum, so I installed a known-working combo drive I had around from a previously parted laptop (Apple branded) and experienced EXACTLY the same situation.
Other things I have tried included using jumpers to manually set the hard drive to slave and cable select (from the factory, with no jumpers, it is set to master), thinking that perhaps the optical drive was somehow seen as master or cable select. All possible jumper settings I tried made no difference.
Booting from external firewire hard drive shows exactly the same situation on the ATA bus, EXCEPT (and this is where it gets just weird enough to pique my curiosity and keep me trying to fix it) - When I boot from the external drive WITHOUT AN INTERNAL DRIVE installed, the SUPERDRIVE SHOWS UP ON THE ATA BUS of the System Profiler! I have not yet seen both at the same time, but I can get one or the other to show, depending on, apparently, the presence of the internal hard drive.
Am I missing something here, or am I to assume a fault in the IDE controller of the logic board?
I have never seen this laptop working properly, but the seller I acquired it from stated that the optical drive worked fine until he fried the DC in-board, presumably with a faulty power supply. He had removed his hard drive to save the data on it.
Thanks for any help or clues that anyone might provide.
See another post with similar situation (archived, or I would have jumped on that thread):
http://discussions.apple.com/thread.jspa?threadID=1862129&tstart=0
Ray

Answer 1

Well, I am happy to report that the situation is resolved with my powerbook not seeing the superdrive, but I still do not really understand exactly why it was unavailable in the system profiler as I originally posted.
My particular solution was to wipe out (erase) the hard drive, zapped PMU, zapped PRAM, did the reset-nvram in open firmware, rechecked to make CERTAIN the proper cables were installed properly, and Now I just completed a fresh install of Leopard from the previously recalcitrant superdrive, to the now-clean hard drive.
My BEST GUESS as to what was wrong with the situation from the outset may have had something to do with where the hard drive came from and how that operating system was installed. (the OS was on the HD when I installed it) In hindsight, perhaps doing all the resets, as well as repairing permissions MIGHT have done it, but I got caught up in thinking it might be cables or something.
So, I would advise others with a similar problem to:
repair the hard drive
repair permissions on the hard drive
reset PMU
reset PRAM
boot to open firmware (hold command-option-o-f at boot) and type "reset-nvram" (without quotes) enter, the type "set-default" enter, then type "reset-all" enter
cross your fingers, knock on wood, and boot! See what happens....
if no glory, THEN look at cables (make certain they are the CORRECT cables and that they are seated properly) I bought a hard drive cable and an optical cable from ebay sellers with assurance that they were the proper cables, and NEITHER had the same part number as the original cable which I suspected faulty, and that in the end are actually GOOD! GO BY PART NUMBERS! do not accept someone elses assurance that their cable is the proper one!
then suspect faulty optical drive - if possible swap another drive in and check.
if a second optical fails, then SUSPECT logicboard, but before you invest in a new logic board ($$$$$) try putting a freshly erased HD in and just see if that helps.
good luck to you all with your mac troubleshooting!
and thanks to all who read and pondered....
I will mark this case "answered" though it is more closed than truly answered.
I am very relieved that the fault did not lie in any of the major components (or even the minor ones for that matter)
It turned out to be only software/installation/settings, even though the symptoms certainly seemed to point to a hardware issue. It pays to try the resets and repairs!
Ray