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Thread: 3,5" Floppy Track 0 Bad fix

  1. #11
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    Quote Originally Posted by igorsk View Post
    a link to said post would be useful methinks.
    Sprechen sie Google? A quick search brings up this post.

    Search terms: "site:vcfed.org eraser microwave"

  2. #12
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    So the TL;DR of the OP is they recommend Linux "ddrescue", with the usual precaution not to bother with lobotomized USB floppy drives.

    Both DOS and many DOS/Windows disk copiers do crap themselves if the boot sector or one copy of the FAT is not readable.

    But the "high tech" way to archive these things these days is something like a Kryoflux or Supercard pro. Some times the various decoders can decode sectors that DOS barfs on.

    Writing data back to a possibly damaged disk is not a great idea. Using a degausser or magnet to wipe the disk just clears any extra "noise", that might make a marginal disk seem a bit more readable until sectors are re-written a few times.

  3. #13

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    I used this software

    http://www.win3x.org/win3board/viewtopic.php?t=25640

    to format bad track 0 disk, and usually works - but don't expect these disk to be reliable ...

    In these days I'm checking a bunch of old disks and my basic rules are :
    Visual inspection for scratched/dirty surface and toss away what's bad (... or clean them if they're just dirty)
    DIR A: and if i can see files then check disk condition with SCANDISK or NORTON DISK DOCTOR.
    If they're fine check for viruses (found NYB.A in dozen of disks... and actually burned an infected BOOT DISK IMAGE as a bootable CDROM too ...)
    Backup them if I need them or
    FORMAT A: /U if there's nothing good on them. IF this fail I use MYFORMAT or downgrade the disk to 720K.
    I tried also to "low level format" some disk with a very strong magnet taken from a broken hard disk but got very
    strange result.

    I actually backupped bad disk with error in track 0 with this software
    https://dmde.com/download.html
    (there's actually a DOS version in 2019!) wich can skip bad sector and copy good ones into a image file.

  4. #14

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    Quote Originally Posted by noppa View Post
    I used this software

    http://www.win3x.org/win3board/viewtopic.php?t=25640

    to format bad track 0 disk, and usually works - but don't expect these disk to be reliable ...

    In these days I'm checking a bunch of old disks and my basic rules are :
    Visual inspection for scratched/dirty surface and toss away what's bad (... or clean them if they're just dirty)
    DIR A: and if i can see files then check disk condition with SCANDISK or NORTON DISK DOCTOR.
    If they're fine check for viruses (found NYB.A in dozen of disks... and actually burned an infected BOOT DISK IMAGE as a bootable CDROM too ...)
    Backup them if I need them or
    FORMAT A: /U if there's nothing good on them. IF this fail I use MYFORMAT or downgrade the disk to 720K.
    I tried also to "low level format" some disk with a very strong magnet taken from a broken hard disk but got very
    strange result.

    I actually backupped bad disk with error in track 0 with this software
    https://dmde.com/download.html
    (there's actually a DOS version in 2019!) wich can skip bad sector and copy good ones into a image file.
    what method to clean the surface of a disk?

  5. #15
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    Remove the cookie from the jacket, rinse with distilled water, put in new clean jacket.

  6. #16

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    Quote Originally Posted by maxtherabbit View Post
    what method to clean the surface of a disk?
    Well, I tried to clean a few disks just using cotton swabs and alchool, and a lot of patience.
    I spent most of the time on a single disk, that was actually scratched and unreadable, and
    I managed to get a clone image, with several errors, but good enough to save some files
    I needed.
    BTW most of the disk I'm trying to recovery contains no valuable data, I just want to reuse them
    after formatting.
    There are a small number of them that I will like to recover but for now I'm gathering experience...

  7. #17

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    Isn't there some dangerous material in microwave magnetron's? Might be worth a warning to some who are unaware of it.

  8. #18
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    No, I don' t think so--if you have a citation that says so, please post it here. The magnets are ordinary ceramic magnets. The rest of the magnetron is mostly glass and assorted common metals.

    Of course, there's a small amount of very dangerous vacuum under the glass--it could mean the end of the universe as we know it if it escapes. /s

    Please, do the research.

  9. #19

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    Here is a link:

    https://www.makeuseof.com/tag/safely...art-microwave/

    Something about beryllium oxide...

  10. #20
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    In the insulators attached to the magnetron itself in tiny amounts. The heater also contains trace amounts of thorium oxide.

    What are you going to do, pulverize the thing and inhale it? Fluorescent lamps contain amounts of the same material--and heaven forfend--mercury!

    The magnets are exterior to the magnetron itself and are quite simple to get at. In the article cited, simply remove the screws on either side of the cage and the assembly will come apart, leaving the magnetron itself intact. From WikiP:

    BeO is carcinogenic in powdered form and may cause chronic beryllium disease. Once fired into solid form, it is safe to handle if not subjected to machining that generates dust. Beryllium oxide ceramic is not a hazardous waste under federal law in the USA.
    I've got a box full of mercury-wetted relays. I suppose that I should call the hazmat team in... And oh my, I've got a box full of 4' fluorescent lamps...
    Last edited by Chuck(G); September 20th, 2019 at 08:10 AM.

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