Installing Leopard 10.5.1 on PowerMac G4 MDD

Question

I have a PowerMac G4 MDD dual processor 1.25 Ghz, 1.024 GB Ram, with 115 GB internal Apple issued hard drive. The ram, keyboard and mouse are Apple original issue.
I am running Mac OS X 10.2.1 (6R73) on the original hard drive.
I am attempting to install Leopard 10.5.1 from an Apple DVD. (The Family 5 pack license) and have not been successful despite many attempts.
The Apple Studio display is connected to an Apple issued video card. The Mac came with an Ultra SCSI card. I removed it.
I installed a new Seagate Barracuda 320 GB ATA/6 7200 RPM 3.5 16 MB on the same buss as the original hard drive. I did not move the original hard drive from its original position. The Seagate hard drive jumpers are set to Cable Select. This drive would not accept installation of Mac OS 10.5. It also would not Verify or Repair. “Invalid B-Tree Header” was an unrepairable error. I exchanged that drive for another identically rated drive, and began again.
I verified the 10.5.1 install disk media twice. No error messages. Visual inspection of disk shows some minor scuffs, but they were on the disk when received. The disk package was sealed.
I have formatted the target drive using Apple Disk Utility--the Mac OS 10.2.1. compatible version. It has passed the Verify routine many times.
I have run the “Install New System and the “Erase and Install” many times.
I have run a CD/DVD lens cleaning disk once. No help.
System preferences set to Never sleep. Screen saver turned off. Not connected to any network during install attempts.
No other PCI cards or any other modifications to the machine.
I created a new Administrator account, logged in and attempted an install. Install failed. Error message: Cannot validate “BaseSystem’ package.
On some install attempts, some files were written to the target hard drive but not enough to constitute a functional system “Install Failed” message appears after about 2-4 minutes.
On other attempts, the install would hang in less than 2-4 minutes.
I have an identical PowerMac G4 MDD dual processor 1.25 Ghz, 1.024 GB Ram, with 115 GB internal hard drive on which the 10.5 DVD Leopard disk installed on an identical Seagate 320 GB hard drive on the first attempt. Both G4’s were purchased new on the same date from the same retailer.
The only differences between my two G4 MDD’s are:
1. that the problem G4 is running 10.2.1 on the original hard drive, and the working G4 is running 10.2.8 on the original hard drive. (I am not attempting to install 10.5 on that drive.)
2. that before installing 10.5.1, I moved the original 115 GB hard drive on the successful G4 to the slower buss and put two Seagate 320 GB drives on the faster buss previously occupied only by the original 115 GB hard drive.
3. I have not checked to see if the ram chips on the two G4’s are exactly identical manufacture, etc. Also have not compared every detail in System Profiler to determine if build number, etc. are identical.
To test the effect of drive position on the problem G4 MDD, I moved the original 115 MB hard drive to the slower buss, and put the Seagate target drive in the Master position on the faster buss cable. An Erase and Install attempt failed. Error message: “The installer could not verify the ‘BaseSystem’ package. Three folders were installed on this attempt. “BaseSystem.pkg.152.Mrqnl2” of zero KB, “Library” of zero KB, and “private” of 64 MB. On a previous attempt, the BaseSystem folder was about 292 Mb.
Sorry this is so long but I wanted to avoid the first thirty questions clarifying things I missed.
I would appreciate your help. Thanks.

Answer 1

Not having a firewire cable at hand, I transplanted the target drive to the successful install G4 so that I was installing on the successful G4 using a "successful CD/DVD drive" on to the target Seagate Drive. WORKED the first attempt.
Believing that the knowledge gained by these tedious exercises in troubleshooting should be shared and added to the public record, the following should be noted.
Clearly, either the problem G4 MDD has a problem, or the CD/DVD drive in the G4 MDD has a problem with installing Mac OS 10.5. A gambler would bet on the CD/DVD drive having some issue and not the Mac G4.
It is noteworthy that the CD/DVD drive in question has successfully read and burned CD's and verified the Mac OS 10.5 Install DVD without error, hence, in all of those actions, indicated no error or problems at all, yet, appears to be the problem. Perhaps INSTALL of Mac OS 10.5 raises some issue with the CD/DVD drive that the other successful actions (reading and burning of CD's) does not raise. I have no other reasonable explanation.
My complimentary Apple Care for my purchase of a family pack Leopard 10.5 treatment was that since I was not installing 10.5 on my "main drive" any help was outside my Apple Care coverage. (The subject drive was on the Master position of the fastest ATA cable, and to my non-technical, dumb lawyer approach to things, was the "Main Drive.)
Of course, a prudent person would install a new operating system on a clean drive without trashing (and jeopardizing) a working operating system (and the data on that drive) until certain that the new operating system was fully functional and non-destructive, before switching to the new operating system. That concept appears outside the scope of complimentary AppleCare. Even more relavant, given comments in the Apple knowledge base about the disasterous consequences of interrupting an install.
Thank you to Eustice who was precisely on track as near as we will probably ever know.
I have spent nearly 8 days messing with this,(well spent)and, read nearly 1,000 questions and replies on various forums on other issues beyond this which have solved many questions I have not posted. To all of the true giants of technical genius who have helped me and so many others in this forum, THANK YOU.