Creating System Floppies for 128K / 512K Macintosh

pl1984

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On occasion I come across 128K and 512K (original, not the 512Ke) Macintosh systems. In order to use them I need to create system floppies. I have the various (1.1, 2.0, 3.2, and 4.1) system images along with complimentary software (Paint, Write, Backup, etc.).

In order to create this media I have used my Macintosh IIci (with Super Drive) running System 7.1, Disk Copy 4.2, and the respective disk images. This has worked flawlessly and reliably. However from time to time I have a need to write different floppies for which the software is not yet on the IIci. The problem with using the IIci for this is how do I get the software onto its hard drive. It does not have an ethernet card nor does it have a built in CD drive. I do have an external AppleCD 300 drive which is what I have used in the past. However it's cumbersome as I have to download an image, move it into a disk image with the HFS (not HFS+) filesystem (as System 7.1 cannot read HFS+), burn it to disc, then insert the disc on the IIci. It's not bad but requires me to burn a CD each time I want to move something to the IIci.

In order to improve the process I decided to purchase a PowerMac 7300 which has built in ethernet, an optical drive, and the all important floppy drive (Super Drive). This allows me to download images on a modern system, FTP (using Fetch) them to the 7300, then write them directly to floppy. Or so I thought. Doing the same procedure on the 7300 fails to create a bootable floppy for these older Macs. The 7300 is running System 7.5.5 (the original version which shipped with this system) and, like the IIci, I am using Disk Copy 4.2 to write the images. I use the exact same floppy (not the same kind, the exact same floppy), Disk Copy shows the exact same checksums (Tag and Data), and successfully writes the image to floppy. However when I go to boot the 128K / 512K systems it doesn't recognize the disk and ejects it.

So, I'm wondering what the issue may be. I may upgrade the IIci to System 7.5.5 to determine if the OS version is the issue. However, during my research, I haven't come across anything which would indicate System 7.5.5 could not be used to write Macintosh File System (MFS) images. Perhaps the difference in drives is the issue (they're both Super Drives but different models).

Anyone have any experience and / or thoughts about this? It's not really an issue as I can move the images between the 7300 and IIci on floppy but it would be nice to be able to make floppies directly on the 7300 itself.
 

pl1984

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If you format a floppy on your 128K, is it readable on the 7300 ?

Likewise, is a floppy formatted on the IIci readable on the 7300 ?
Yes to both questions. I formatted a floppy on the 128K, created a test document in Write and saved it to the formatted floppy, then loaded the document on the 7300 with TeachText. I have moved files between the IIci and 7300 on multiple occasions without issue.
 

MacTech68

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You could try a swap of the floppy drives (IIci to 7300) as a temporary troubleshooting step.

Or, If you can find a head cleaning floppy, try cleaning the 7300 floppy heads.

Use "TechTool v1.2.1" which has a Floppy drive Head cleaning button - handy to move the heads back and forth on a cleaning disk.

https://www.micromat.com/component/k2/item/285-techtool-121

A word of warning. Do NOT lift the top head too high (certainly not much higher than it is when fully ejected) if you decide to try a manual cleaning. The tension spring is easily stretched, destroying any chance of the drive working again.
 

pl1984

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You could try a swap of the floppy drives (IIci to 7300) as a temporary troubleshooting step.

Or, If you can find a head cleaning floppy, try cleaning the 7300 floppy heads.

Use "TechTool v1.2.1" which has a Floppy drive Head cleaning button - handy to move the heads back and forth on a cleaning disk.

https://www.micromat.com/component/k2/item/285-techtool-121

A word of warning. Do NOT lift the top head too high (certainly not much higher than it is when fully ejected) if you decide to try a manual cleaning. The tension spring is easily stretched, destroying any chance of the drive working again.
I think that may be my next step. At least they're easy to swap.

I've already cleaned the heads in the 128K and 7300 (I have a floppy disk head cleaning floppy). I have manually cleaned the heads on a lot of floppy drives (from 400KB through 1.44MB drivers). Just about every 400KB and 800KB drive I've come across has required removal of the old lubricant due to its gumming up over the years. A little lighter fluid to remove it, a little electronics cleaner to loosen it up, and a little electronics cleaner / lubricant to get it working again. Oh, and a whole lot of Q-tips!
 
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bunnspecial

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I've made bootable Macintosh 400K and 800K floppies in a beige G3 running OS 9-I'm sure that the OS isn't the issue.

With that said, you CAN always Appletalk the files over to the IIci from a newer system-doing that has saved me many times on a system where I didn't have a lot of ways to get stuff on otherwise(especially PowerBooks, where I have even at times done AppleTalk over IrDA). You need a printer cable to do this along with built-in serial ports and need to be running OS 9 or earlier. Otherwise, it pretty much just works.

As a side note-since you mention cleaning 400K and 800K drives-I never even try to power up a floppy drive of this age without cleaning it first. The likely result is a broken gear if you do-I have replacements on hand(there are a few sources out there) but would rather not have to use them.
 

pl1984

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I've made bootable Macintosh 400K and 800K floppies in a beige G3 running OS 9-I'm sure that the OS isn't the issue.
This is good to know. I am going to try swapping drives to see if that solves the problem. Unfortunately I've been busy with other things so haven't had the time. I'm going to try and get to it today.

With that said, you CAN always Appletalk the files over to the IIci from a newer system-doing that has saved me many times on a system where I didn't have a lot of ways to get stuff on otherwise(especially PowerBooks, where I have even at times done AppleTalk over IrDA). You need a printer cable to do this along with built-in serial ports and need to be running OS 9 or earlier. Otherwise, it pretty much just works.
Funny you should mention this as I just posted about an ethernet card I picked up for the IIci. If I can find the drivers then I should be good to use ethernet to move the files. If not then my plan would just be to use floppies. I can use the PM7300 to download the files and write them to floppy. Since they're 400/800KB files they'll easily fit on a 1.44MB floppy.

As a side note-since you mention cleaning 400K and 800K drives-I never even try to power up a floppy drive of this age without cleaning it first. The likely result is a broken gear if you do-I have replacements on hand(there are a few sources out there) but would rather not have to use them.
I don't power them up beforehand as it's obvious they're jammed. My process involves cleaning them of all solidified lubricant and then testing them. I've become very familiar (having clean over 50 of the various models) with them and their mechanical operation. Thankfully cleaning the lubricant generally gets them working again.

Regarding the gears, at least for the 800KB drives, they're interchangeable with the earlier 1.44MB drives. This makes it much easier to replace than trying to source the original drive or buying the 3-D printed parts (which work great as I've gone that route too).
 

pl1984

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Wanted to provide an update. I attempted to swap the Macintosh IIci drive (actually the same model but not same revision) into the PowerMac 7300 and it does not work. I assume that swapping the PM7300's floppy drive into the IIci will not work so I haven't bothered to do that. At this point I'm still puzzled as to why I can't write these disks on my PM7300.
 

MacTech68

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7.5.5 should include the floppy format fix (rolled into the system suitcase IIRC).

Does this machine have a third party accelerated CPU card ? Cache DIMM ?

Otherwise, I'm still thinking it's a hardware problem with disk interchangeability, although, I've heard that 73/7500s may have intermittent issues creating MFS boot floppies ! AAARGH. :confused:o_O:mad:


LATE EDIT: Which specific model of floppy is in the 7300? (there was Sony, Mitsubishi and Panasonic IIRC)
 
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pl1984

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7.5.5 should include the floppy format fix (rolled into the system suitcase IIRC).

Does this machine have a third party accelerated CPU card ? Cache DIMM ?

Otherwise, I'm still thinking it's a hardware problem with disk interchangeability, although, I've heard that 73/7500s may have intermittent issues creating MFS boot floppies ! AAARGH. :confused:o_O:mad:


LATE EDIT: Which specific model of floppy is in the 7300? (there was Sony, Mitsubishi and Panasonic IIRC)
The floppy drive is a Mitsubishi MF355F-3592MA. It has a 200MHz 604e CPU card installed and no L2 cache. The version of System 7.5.5 it was running is the machine specific version.

I would think the version of MacOS that I'm using should be irrelevant given I'm working with disk images and not attempting to create my own. But I've decided to try and eliminate as many variables as possible so I dropped down from MacOS 9.1 to 7.5.5.
 

MacTech68

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One thing I did find with these drives is the two worm drive bearings may need cleaning and/or lubrication.

(LATE EDIT: - Do NOT undo the screws holding the worm-drive motor - this will cause misalignment)

To test, move the head assembly towards the centre hub (you may need to do this by manually rotating the worm drive with your finger), then apply power to the drive. The heads should quite rapidly move to the outer edge at a smooth, regular speed. Any stuttering indicates gummed up bearings either at the chassis end or the motor's own bearing.

Also clean the track zero optical sensor with forced air and/or a small brush. Do NOT loosen the screw holding the track zero sensor circuit board, as this will cause a misalignment of the track zero position which is critical for reading/writing boot sectors.

Mitsubishi MF355F-3592MA Annot.jpg
 
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pl1984

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I examined the operation of the drive and everything appears to be OK. I substituted a Sony drive and had the same results. At this point I do not suspect the drive is at issue.
 

pl1984

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Indeed. Sounds about right. :D
I should probably clarify the statement to be clear I mean the individual drive installed in my PM7300. I'm beginning to suspect it may be an issue with the type of drive. In the next few days I may upgrade the IIci to 7.5.5 and try writing images using the same version of Mac OS installed on the 7300.