Why does my optical drive spin down without reading the disk?

I have a Pismo 400MHz with a new PRAM battery, new 80 GB hard drive, I GB of RAM and running Tiger OS 10.4.11 with all updates and permissions repaired.

I installed the OS through my iBook G4, the Pismo in Target Disk Mode. I hadn't used the optical drive on this machine yet, so after the OS install I tried to boot with AHT, The original Install DVD, other misc cds and DVDs. The optical drive will make some noise, spin up and then spin back down, with nothing mounting to the Desktop. I can run my external DVD drive just fine through a USB port, but nothing happens with the optical drive.

I switched out the optical drive with two other known working drives from my other Pismos with exactly the same result. I zapped the PRAM and reset the PMU with no change.

Oh, and I did run Apple Hardware Test (TechTool) from the external DVD drive and it passed all tests.

What a ghost this is! Do any of you kind Pismo people happen to know what is going on? Bad Power Board?

Thanks,

Randy