Software RAID Mirror set degraded?

I’m in dire need of ANY tips you guys might have regarding OSX’s software RAID. I can only find one Apple KBase instance that relates to what is happening on my system, and it’s mostly about Xserve RAID.

Here’s what I’ve got:
Power Macintosh Server G4/500 With OSX [I think is the full name]
OSX 10.3.4 with latest patches
1GB RAM
1 SCSI controller [came with the system]
18 GB Quantum Fireball [ditto]

Sonnet ATA133 controller
2 160GB Matrox IDE drives

I used Disk Utility to create the mirror set, and all had been fine until
this weekend. I happened to look in DU, and noticed that the RAID status was ‘degraded’.

Ran diskutil checkRAID and it showed both slices as ‘OK’, but the RAID
status as ‘degraded’. Rebooted, etc etc, no love.

Interestingly, if I booted into singleuser mode, I saw
‘AppleRAID::something slice timeout’, and then upon ‘exit’, allowing the system to come up into full GUI mode, DiskUtil would show disk0 as missing.

Backed everything up to spare 250GB.

Replaced disk0 with a new 160GB drive.
Initialized new 160GB drive.
[I forget exactly] did ‘diskutil repairRAID disk4 1 disk1 disk0’ [disk4 is
the RAID disk, 1 is slice 1, the missing one, from disk1 to disk0]

This took about 4 hours.
When it finally got done, the RAID was still degraded.
I rebooted, started DiskUtil to see what it’d say, and it immediately started rebuilding the RAID. It seemed happy, so I let it rebuild overnight.

When I checked this AM, it was still rebuilding, then it stopped.
‘diskutil checkRAID’ showed the RAID as degraded, still. Rebooted, and
DiskUtil is rebuilding it again.

At this point I should really consider torching the RAID, rebuilding it,
and starting over from backups. I really don’t want to do that, because
since iTunes is ‘inode-aware’, it would forget about all of my MP3s, which defeats the point of ripping and rating my household’s CD collection.

Any help or hints you can provide would be much appreciated.