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ginoledesma Jun 13, 2001 12:36 PM
SCSI Horror: Fixing up an old mac
Hi, guys. I need help. :)

I have an old Mac LC 575 whose hard drive has just quit after 7 years of continued use. I foresaw this happening and am not worried about the data. I recently acquired 6 SCSI hard drives from a friend and thought that I could just swap one with the other and start over again.

Unfortunately… the drives that I got aren't really the easiest to configure (and I thought IDE drives were a horror).

What my Mac currently has is a built-in CDROM which is set to ID3. My internal drive is dead, so its blank. I have an external SCSI case which has an on/off termination and a selectable SCSI ID.

The only rule I remember about SCSI is: devices on the end should be terminated. That's that.

The first thing I tried to do was set one of the drives (Seagate ST39200N) to be ID0. I also have another drive (Maxtor MXT-540S) to be ID6, which is sitting inside the external SCSI drive bay whose on/off termination is set to off and SCSI ID at 6 as well.

I can boot using my System CD, but when running Drive Setup or SCSIProbe 5.0, nothing in the SCSI bus is listed, except ID7 which is Macintosh. The drives spin up at startup (LEDs blink). That's that.

I've been fiddling around with the drives but after doing so my Mac wouldn't boot anymore. I didn't touch the SCSI jumpers of the CDROM drive, so I have no idea whether its terminated or not.

I'm confused as to some terms such as "terminate SCSI power TO cable", "terminate SCSI power FROM cable", "terminate SCSI power TO drive", "FROM drive", Parity enabled/disabled, etc…

Any advice is really appreciated. Thanks. :)
<SpinyNorman> Jun 13, 2001 02:03 PM
Are you setting the SCSI ID via jumpers? Because you can't just drop the SCSI device in a case and use the selector to pick your ID unless that selection is communicated to the drive inside. In addition, the devide inside the external case needs t be properly connected to the ID selctor via the cable that attaches to the jumper pins. It's easier to manually set the ID via the pins and then pop it into the case.

If you've already done all of the above and are still having problems, check the cable.
ginoledesma Jun 14, 2001 04:51 AM
I'm not using the id selector or terminator cables of the SCSI case. I was well aware of that from the start (since I couldn't find any place to plug them to). :)

The cable works fine, since it works for my friend's PC SCSI system.
zac4mac Jun 14, 2001 12:05 PM
SCSI term power should be off. Your MoBo will supply that.
First and last(Physical, dictated by cabling, not by address #) in chain terminated.
Some hard drives will not be recognized by Drive Setup, try LaCie Silverlining or FWB HD Toolkit.
Good rule of thumb is to use ID's 0-2 for HD's, 3 for CD, removeable drives like Zip, Jaz on 4 or 5. Scanners like to be last at 5 or 6.
etphonehome Jun 14, 2001 10:12 PM
SCSI is a very weird thing. On my old PowerBook 160, I have an external hard drive and CD-ROM drive that I attach when I'm at home. Anyway, when the hard drive is connected directly to the computer and the CD-ROM drive is connected to the hard drive, everything works fine. However, when the CD-ROM drive is connected to the computer and the hard drive is connected to the CD-ROM drive, the computer won't even boot!

My advice to you is to fiddle with all of the settings you can (jumpers, cables, anything) until it works. Then, DON'T MESS WITH IT!!! Once, I even had a different external hard drive work when the cable was plugged into the top SCSI port, but it didn't work when the cable was plugged into the bottom port. Anyway, there are often mysterious reasons why SCSI will or won't work. When it finally does work, just thank God and don't ask any questions about why it works.
ginoledesma Jun 15, 2001 11:22 AM
Thanks a lot, guys! :)

I'll try out your suggestions. Yes, I was well aware of Drive Setup not being able to detect my drives. I still remember the old warnings from Apple that only "Apple-shipped" hard drives will be recognized by their software (which was particularly true with Apple HD SC Setup).

I have Drive Setup 1.3 for the Mac, which came with Mac OS 8. There're newer versions and they'd probably be able to detect the drive but I've no way of transferring the file to the Mac since its floppy drive is busted. Sigh!

This is an observation I made: when I have a drive (ID0) plugged inside the Mac, CDROM (ID3) in, and an external drive ID4, SCSI Probe 5.0 says Apple Bus Unknown and only lists Macintosh LC 575 (ID7). CDROM Drive isn't listed but I am able to mount CDs (I'm booting off the RAM Disk).

I'll try to fiddle a little bit more, but the drive inside the Mac doesn't seem to spin up (I can't hear it, but maybe that's just it) but the drive outside does.

Right now, I've set the internal drive and external drive to be terminated, like so:

X --- Internal HD (ID0) ----- CDROM Drive (ID3) ----- External HD (ID4) --- X

where X is the termination.
ginoledesma Jun 15, 2001 11:25 AM
I'll probably burn a bootable CD-R with tools like FWB Hard Disk Toolkit and the latest Drive Setup. Hmm, the only problem is, my CDROM drive in the Mac LC 575 takes forever to load some CD-Rs.
<anonymous> Jun 15, 2001 12:40 PM
drewman Jun 16, 2001 07:08 AM
Don't terminate the first hard drive as the motherboard is the first device in the chain (ID7) and is already terminated.

Walter J. Ferstl Jun 17, 2001 08:41 AM

you write:

"My internal drive is dead, so its blank."

Does that mean that you did not take this dead drive out?

In addition to all the other advice given here, let me tell you about a problem I had with a similar Performa once. In this case, the internal CD drive was SCSI ID 3 as usual. But the whole thing did not start unless I switched an external scanner that had SCSI ID 3 (on the external SCSI bus, of course, which should be not a problem in theory) to some ID other than 3. This Performa was one with an IDE internal hard drive, so your situation might be different.

My suggestion is to put in one of your new SCSI drives internally using the same plug the dead drive had, with all jumpers off (= ID 0), first off with no termination jumper applied.

By the way, an external drive does not work with its ID set to 0, as far as I know.

Good luck,


[ 06-17-2001: Message edited by: Walter J. Ferstl ]
ginoledesma Jun 18, 2001 12:46 AM
Thanks for the replies! :)

I've managed to progrss, albeit not too far. The dead drive was removed beforehand.

Right now, I managed to make my Mac work with an external HD set to ID0, with termination on. As of the now, my setup is:

&lt;term&gt; --- CDROM (int; ID3) --- HD (ext; ID0) --- &lt;term&gt;

I've noticed, however, that when I put my ext HD inside (with ID still set to 0 and unterminated), my Mac starts searching for SCSI devices again. This also happens when the internal drive is terminated. So in either case -- terminated or not -- my Mac doesn't boot up.

Here's what I found out, however. Whenever the hard drive is placed inside the Mac, it doesn't seem to power up. I don't hear the hard drive spinning. To be sure this was really the case, I got a drive with a built-in LED that starts up when its powered up. When I placed it inside the Mac, the LED didn't light up. Putting it on the external drive makes it power up, however.

I've set the drives to "MOTOR START ON POWER UP" but this didn't change a thing. I'm guessing my internal HD has gone bad (I hope NOT!!!).

I'd really like to add another HD to my Mac as my current one isn't too large, though it is bootable. Hmm... Is there a way to add another SCSI HD device to my chain without requiring another hd case? Are there SCSI cables that are similar to ATA cables that allow 2 drives to be connected to one channel? Or am I just hoping against hope? :)

Thanks again...
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