Macintosh LC 475 Zip Problems

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Macintosh LC 475 Zip Problems

After finally getting my macintosh LC to boot from a floppy disk (It doesn't have a hard drive, I connected an external scsi zip drive, And I planned on having it use the zip disk to boot, and floppies to get more data. However, the zip disk has only showed up say, 3 out of 50 times I have started up the computer. I have tried 2 different scsi cables, and 2 differnet zip drives. Any ideas on how to get it working?

Macintosh L.C. 475-OTHER, Other OS, Needs hard drive and monitor cable

Posted on Jul 19, 2012 5:50 PM

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Answer 1

Jan Hedlund

Level 7

22,201 points

Jul 19, 2012 9:58 PM in response to nstephenh

To begin with, has SCSI termination been checked? If necessary, see the article below. In which position is the termination switch on the Zip drive?

http://support.apple.com/kb/TA27743

Jan

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Answer 2

nstephenh Author

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Jul 20, 2012 7:48 AM in response to Jan Hedlund

The scsi id is 5, and termination is on.

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Answer 3

Jan Hedlund

Level 7

22,201 points

Jul 20, 2012 11:32 AM in response to nstephenh

Since the internal hard drive has been removed, the situation is special. Sometimes one has to experiment a bit with SCSI termination. For example, what would happen with (another) terminator near the SCSI port?

The following article could perhaps be of some interest to you.

http://lowendmac.com/tech/termination2.shtml

Jan

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Answer 4

Jeff

Level 6

12,058 points

Jul 20, 2012 11:37 AM in response to nstephenh

It sounds like the problem is with the disk itself or the disk's bootable content. What OS version did you copy to the Zip disk, to boot the LC475? Did you copy it from a CD or floppy startup disk? Are you using the 4-key combination (Command + Option + Shift + Delete), to boot from the Zip drive? I assume that you want to retrieve data from the floppy disks, and copy to the Zip drive.

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Answer 5

nstephenh Author

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Jul 20, 2012 11:52 AM in response to Jeff

On one of the times the zip disk showed up, we tried to install system 7.5 from disk images downloaded from the web. However, booting from it failed, so we gave up on that and threw the disk back into the box. If we can get teh zip disks to show up consistently, then we will try booting from it, bt If the don't even mount then ther is no hope of booting from them. We have tried numrous zip disks, labeled maczip, or just zip, in the lower right hand corner.

We will try changing the termination, but the zip drive is terminated. I also have a hard disk which I am not sure works, and an external terminatir we can put on the cable. Perhaps the lack of hard disk requires some internal termination. I will check and see if there is any way of doing that. Does anyone know if there are certain pins I could solder together to get it to terminate internally? I noticed that on many terminators, it is just a resistor connecting some pins.

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Answer 6

Jeff

Level 6

12,058 points

Jul 20, 2012 12:09 PM in response to nstephenh

You need to format the Zip disk as a Mac OS Standard (HFS) volume, and not a Mac OS Extended (HFS+) volume. A PC-formatted Zip disk will not boot that computer. The System 7.5 OS build must be installed on the Zip disk, while it's connected to a comparable 68K Mac, so that the necessary hardware drivers are written to the disk. You won't boot the LC, using an image of a PowerPC Mac's OS build.

If the internal SCSI ribbon cable is still inside the case, you could install an active IDC-50 (male) terminator on the cable's last connector. Depending on what you're attempting to do - such as data retrieval, you may find a less expensive solution by checking any thrift stores in your area, for a slightly newer, used Mac. Several years ago, beige G3s could be purchased for $20.

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Answer 7

nstephenh Author

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Jul 20, 2012 12:14 PM in response to Jeff

I formatted a few of them on my blue and white G3. I will try again, but I don't think disk format is the problem, as a disk mounted once, but not the time after that, with no apparent change.

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Answer 8

nstephenh Author

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Jul 20, 2012 12:29 PM in response to nstephenh

A zip just showed up now, so the previous 50 tries 3 succeses is now more like 55 tries 4 successes. The disks are formatted hfs and the zip disk that has the system appears to be working. After restarting the computer, however, the zip disk failed to mount.

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Answer 9

nstephenh Author

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Jul 20, 2012 12:49 PM in response to nstephenh

thanks to all of you, it is finally working.

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