Damaged floppy disks repair advice needed

I have a set of two 3.5” disks which suffer from the same problem. The magnetic media is detached from the central metal ring. I want to transfer the magnetic media to another case and glue it again to the new “donor” floppy ring. What kind of glue should I use that would be strong enough but would not damage the media ?


  • edited January 2021
    Having done that a number of times, that is insanely difficult.

    There are two huge problems:
    1: When reattached, there is a 99% chance the index will no longer match the beginning of the track. Unlike 5.25" and 8" media which has a hole in the magnetic cookie, 3.5" disk rely on the position of the metal hub. You will have problems reading such disks with a normal floppy controller or USB floppy drive. A Kryoflux or SuperCard Pro, however, can deal with this.

    2: When reattached, there is about a 90% chance the radial alignment will be off. When de-attached, the plastic cookie does not fit firmly around the hub. The hub can move up/down/left/right a little. At the factory, the cookies are attached to the hub "gravitating" to one side. Once de-attached you have no way of knowing where it was supposed to be. The only way to deal with this is through trial and error, attaching the hub, reading in with a Kryoflux so you can see how far off the tracks are (track 1 or 2 may bleed through to track zero, for example), de-attach it again and re-glue it at a slightly different alignment.

    I don't recommend it, but I've used tiny amounts of superglue (placing a blob on a piece of paper, dabbing one end of a paper clip in it then touching the paperclip to the hub in 2 or 3 spots.) That dries fast and is easy to re-break. It does get very, very messy. It can easily damage the media, and looks ugly.

    I've managed to recover a couple of disks like that using a Kryoflux, but each time it has been a nightmare.
  • Thanks for the comprehensive answer. It looks like it’s going to be very difficult. I have an SCP board so the first point shouldn’t be too hard. The second part is more worrisome and I’m afraid to damage the floppies. Maybe I can investigate another way of recovering it.
    The software I want to preserve is Bridgeport EZ-Draft CAD for Macintosh 512/plus which is quite rare. I have a set of disks as replacement of those defective disks in the box but I can’t make the software run on my Mac Plus. The master disk is a 400k disk and seems to be copy protected. Copies of the disks with disk copy 4.2 are rejected when I start the software but those with copy ii plus are not but my Mac freezes just after.
    If I use the original disk, it’s accepted but my Mac freezes also. Could also be an issue with my Mac Plus.
    Any suggestions I could try to dump the disks and post it so that someone can test on another Mac ?

  • Ouch. I have had no luck writing protected Apple 400k/800k 3.5" floppy disks.

    One tip, when archiving with a SCP be sure to use splice mode and select at least 3 revolutions. (For some reason the PCE tools don't always like the first or last revolution so you need one inbetween).

    Also, be sure your 3.5" drive can handle the odd frequencies. Make sure it works ok with a non-protected Mac disk first.

    Once dumped, your best bet would be to try to get the program running in PCE-Macintosh. That can actually handle some copy protection schemes.

    Please do post dumps of it so others can take a look at it and verify that you got all the bits off of it.
  • @SomeGuy here are the dumps of the disks. I used Disk Copy 4.2 for the disks that are not copy protected. Note that "Lessons" disks is not an orginial disk. For the master disk, which is copy protected, I dumped it with SCP and Deluxe Option Board.
    The Master disk doesn't seem to work on my Mac Plus, so I'm not even sure the original disk is working.

  • Ok, thanks. Just a quick test with PCE-Mac, it keeps asking for the master disk while spitting it out. I'm guessing it does not like the copy protection.

    When you ran it on your Mac Plus, did you boot from the system disk they provided? It could have some stuff it needs on there.
  • Interesting. Looking at a flux view, track 4 sector 5 shows nothing but noise, kind of like laser hole protection. Then track 4 sector 11 looks like valid encoding but with an intentionally bad CRC.

    In PCE-Mac, nothing seems to write to the sector, but the debug console shows some IWM exception.

    Does the manual say the disk needs to be non-write protected in order to run?

    I would not try un-write protecting the originals to test that, but does the copy II plus or transcopy copy behave differently between write and not write protected?
  • edited February 2021
    @SomeGuy :
    “did you boot from the system disk they provided?”
    Good catch. I did make some progress :
    1)boot from system disk.
    2)Install software on hard disk using setup procedure in manual (see PDF),
    3)run set options and set data location as described in manual
    4) run program
    5) asks once for master disk (write protected is ok)
    Done (see below). I did test several copies of master disk but none of them were accepted.

  • Very nice. By "ask once" do you mean that subsequent times you launched the application on the hard drive it did not need the original disk?

    If so, then it should be possible to create a hard disk image that can run in an emulator.

    Slight clarification, earlier you said you tried to copy it with "copy ii plus" did you mean your "Copy II PC Option Board" AKA Transcopy?

    Later versions of Copy II Plus on the Apple II actually can bit-copy 3.5" disks.

    Have you tried copy II Mac? https://winworldpc.com/product/copy-ii-mac/7x

    Did you have any luck writing a duplicate of the disk with the SuperCard Pro? (I can't even duplicate non-copy protected Mac GCR disks with mine).

    BTW, could you re-dump the Lessons, System, and Utility disks with the SCP set to "Splice" mode and at least 3 revolutions? If I'm looking at those right it looks like you used index mode, which won't work for most Macintosh GCR disks. (But the DiskCopy 4.2 dumps do have the data).

  • It asks for the master disk at each startup of the program and I must insert the original disk (write protected is ok). After verification It’s ejected and asks for system disk again and then asks for the master disk again but this time it must not be write protected. I can insert one of the copy I make and it’s accepted this time.
    I used copyii Mac 7 and deluxe options board. What option in copy ii Mac would you recommend (keep length, sync) ?
    With DOB there are many possible options, what would you recommend ?

  • Well, with the deluxe option board you would need to use TCM (TransCopy "Multi") instead of the standard TC copier.

    Off hand, I don't believe length or sync would make any difference. The disk is not index aligned, and I don't believe aligning to index would make any difference.

    In this case, I think the hard part about copying this protected track would be re-creating the "noise" located within the first intentionally bad sector. But then again, I don't really know what the protection code is looking for.

    Unfortunately, I don't have a Mac of that vintage to test on here.
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