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A possible fix for a highly unstable G3 or G4 Tower
Authored by: johnsawyercjs on Sep 08, '05 04:15:05PM

It's just as likely, if not more so, in most cases, that it's the hard drive that's beginning to have problems. The submitter of this hint didn't say if he tried a known-good hard drive on the logic board's hard drive ATA bus. Whether the problem is the hard drive bus or the drive that's plugged into it, the symptoms can be the same. However, I could see where the components in the hard drive's bus could age too--like everything else, they age due to heat, wear due to electrons flowing through them, etc.--not much you can do about it. You might be able to reduce the wear by keeping your Mac cool (install an extra fan or two; don't let sunlight directly hit the Mac; etc.), but I don't think this would help much unless your Mac is otherwise running unusually hot.

Placing a hard drive on the logic board's CDROM drive's ATA bus simply makes the hard drive run slower, which can eliminate a lot of problems if the hard drive's components have begun to age, and are no longer able to run at ATA33 or ATA66 speed. In the B&W G3, my timing tests show it to be about 75% of the speed of the G3's ATA33 hard drive bus; the speed difference will be more pronounced in the G4, which has an ATA66 hard drive bus. The CDROM drive's bus in the B&W G3 is ATA-3, and in the G4 too, I believe--not ATA33. ATA-3 runs slower than ATA33, etc. Some say ATA-3 runs at half the speed of AT33, but that's not the case--just about 75% of the speed.

The B&W G3 is the model that's particularly sensitive to these issues. The size of the drive on a B&W G3 can also be an issue--I've found that the B&W G3's hard drive bus, even the rev 2 B&W logic boards that have an improved ATA bus controller chip that allows the hard drive bus to run a master/slave drive configuration without data corruption, can't take drives larger than about 20 or 30 gigabytes. Larger drives on a B&W G3 can often cause intermittent bad behavior--intermittent failure to boot, crashes, directory and file damage, failure to copy files to and from the drive, etc. I don't remember if dividing the drive into 20 gig maximum volumes helps, but I don't think it does.

Though some hard drives will have problems in the B&W G3, many others will work fine--you just have to try them to find out. One utility I've found that will pretty reliably tell you if there's a problem with read/write accesses, is LaCie's old "TimeDrive" utility, version 3.0 or later--it came with the Silverlining formatter. Unfortunately, they don't seem to have it on their web site any more, and it's not on VersionTracker. Other utils like Techtool might properly tell you if there's a problem though. Another test that can often indicate if your drive is working OK, is to use the Finder to duplicate a multi-gigabyte (2 gig or larger) folder full of files, and see if you get any read/write errors.

On G4s, these bus problems are much less common, so I'd try a known-good drive on the logic board's hard drive bus before you move the potentially problem drive to the CDROM bus.

Also check out Applecare document 31347: "Power Mac G4 (Digital Audio): 40 GB and 60 GB Hard Drive Issue", for info on how some of the drives Apple installed, have these problems.

One way to get a G3 or G4 to handle larger, newer hard drives properly, at full speed, is to install a PCI slot ATA card (Sonnet Tempo, etc.), and connect your hard drive to it. The rev 2 B&W G3 logic board will allow two or more drives to be connected to these cards, but if the G3's logic board is a rev 1, often you can't connect more than one drive to the card, and you might not even be able to plug another drive into the logic board's hard drive bus--doing so can introduce instability again. If you need to run two drives in a B&W G3 rev 1, especially larger newer drives, the most reliable arrangement is one drive connected to a PCI slot ATA card, and the other connected to the CDROM drive bus.

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A possible fix for a highly unstable G3 or G4 Tower
Authored by: bdog on Sep 08, '05 10:13:38PM

There are so many troubleshooting steps I didn't want to list them in the hint. But yes, I did try replacing the HD, every time. This hint is one of the last things you should try, since a bad HD, bad RAM, corrupt PMU and/or PRAM are all much more likely.

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A possible fix for a highly unstable G3 or G4 Tower
Authored by: imageworx on Sep 09, '05 09:15:30AM

Why not get a PCI-ATA card that can boot an IDE drive? Might even try a ATA-133 RAID-compatible bus card (make sure you use the appropriate cable).

Like all things, its likely that we get a lemon now and then (a delicate trace, a resistor issue, a logic problem, a nicked ribbon cable, environmental...) and this could be interpreted as such.

However, I've seen some oddities where they are unexplainable at the moderate level. Some tricks like setting drives to Master and Slave from CS have resolved this. Or replacing the CDROM/DVDROM drive with a Burner has improved transfers...on the other bus!

Its like SCSI Voodoo all over again! But without the IDs...

To BeOS or Not to BeOS

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A possible fix for a highly unstable G3 or G4 Tower
Authored by: bdog on Sep 09, '05 10:03:48PM

Well, this fix dosn't require the user having to buy anything.

Yea, CS versus Master or Slave can also make a difference in certain cases.

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