[G4] G4/500 AGP - ATA-3 (ATAPI) controller going?

[Jim Pacyga]

Anyone with a Sawtooth (AGP graphics) PowerMac G4 ever seen these 
symptoms:

Load a DVD into the drive, it cranks around a bit.  DVD player can 
start and sometimes even play a bit, but then a popup says "Device 
removal" - the drive starts cranking around like crazy.

After a few times, the machine failed to allow itself to be put to 
sleep (or more accurately - awoke immediately)- a CMD-OPT P R PRAM 
reset fixed this symptom - but did not fix the drive problem.

System.log records a media READ or WRITE failure (with the message 
repeating endlessly).  Sometimes the drive comes back other times not.

I have pulled the DVD-RAM drive and replaced it with a working DVD-ROM 
drive and get the same results.

Do I have any options?  My thoughts were:

1) Try the cable to see if it is faulty (probably not)
2) Either get a new PCI card adaptor (is there one, never looked 
before) or
3) ???

System:
G4/500/AGP
Radeon 8500 w/126 ROM & ATI Displays 4.2
640 Mb RAM
Sonnet SATA Controller - 1x200Gb
2x80Gb internal ATA-4
Airport
Harmon Kardon Soundsticks
OSX 10.3.6 with all updates.

The problem happens on a previously working 10.2.8 install that I also 
have on the system - so it doesn't appear to be related to the new ATI 
drivers (not that it should) or any other strange 10.3.6 update.