Image Map Image Map
Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Macintosh 512k 400k disk drive not reading/formatting

  1. Default

    Quote Originally Posted by Mac View Post
    There is a local hacklab that has several oscilloscopes. How big of a project would it be to hook one up to this to do the calibration? Any literature available on doing that?
    Have you looked at the documents in this Bitsavers directory? There is some good technical documentation in there.

    Quote Originally Posted by mwillegal View Post
    Rotational speed could be a bit slow, which would prevent a track's worth of data from properly fitting. I can't remember if there is any adjustment for that.
    Rotational speed is, to some degree, self-correcting to compensate for factors such as thermal drift.

  2. #12

    Default

    Quote Originally Posted by mwillegal View Post
    ...you might still have a slightly sticky mechanism, which could prevent the head from getting properly positioned when seeking.
    Actually, I did forget to mention that! The stepper that drives the read/write head does sound rough. I can rotate it with my finger, but it does feel a bit stiff. What's the recommended lube for something like this?

  3. Default

    The mechanism should operate smoothly. The old dried up grease in these drives can be difficult to remove, but take the time to get all the old stuff off. You should use a light plastic compatible grease to lubricate - you can find these sorts of lubricants at hobby stores.

    Some kinds of lubricants can attack some certain kinds of plastic, hence the plastic compatible grease.

    regards,
    Mike Willegal

    Quote Originally Posted by Mac View Post
    Actually, I did forget to mention that! The stepper that drives the read/write head does sound rough. I can rotate it with my finger, but it does feel a bit stiff. What's the recommended lube for something like this?

  4. #14
    Join Date
    Apr 2018
    Location
    Los Angeles, CA
    Posts
    620

    Default

    Quote Originally Posted by mwillegal View Post
    The mechanism should operate smoothly. The old dried up grease in these drives can be difficult to remove, but take the time to get all the old stuff off. You should use a light plastic compatible grease to lubricate - you can find these sorts of lubricants at hobby stores.

    Some kinds of lubricants can attack some certain kinds of plastic, hence the plastic compatible grease.

    regards,
    Mike Willegal
    Yeah, i've noticed that whatever grease they used on those old mac drives turns into cement practically over time... Worse than any other drives i've dealt with. I've had the best luck just spraying canned oil/lubricant into the area where the grease is to basically re-moisturize it and then move the part a bunch.. Once it's sorta working, use some kind of disk exerciser program (or a lot of copying/deleting) to get everything moving again properly. Go ahead and use plenty of oil, there really isn't such a thing as too much as long as you keep it away from any head, belts (luckily no belts on mac drives) or sensors. (I feel like this is a bad recommendation because someone would let oil drip all over and that's not what i mean, i just mean that using it sparingly is more of a waste of time then anything)
    -- Brian

    Working Systems: Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA
    Project Systems: Amstrad PCW 8256, Kaypro 2/84 (Bad Chips: 81-194, 81-189).

  5. Default

    Quote Originally Posted by ngtwolf View Post
    Yeah, i've noticed that whatever grease they used on those old mac drives turns into cement practically over time... Worse than any other drives i've dealt with. I've had the best luck just spraying canned oil/lubricant into the area where the grease is to basically re-moisturize it and then move the part a bunch..
    I've developed some different techniques over time. Here's what I last did:

    I removed the top metal "cassette" part that holds the floppy, and where all the grease hardens. I dipped it in a pot of boiling water. Took it out, waited for it to cool a bit, then used a rag to wipe off the grease.

    Reassembled, and all worked fine.

  6. #16

    Default

    Final update, I hope!

    I relubricated the worm drive of the read/write head, and now it reads and formats disks no problem.
    I still need to source some more DD floppies though. Anyone know of any European shops selling them? I'd like to avoid the shipping hassle of ordering from floppydisk.com.

  7. #17
    Join Date
    Apr 2018
    Location
    Los Angeles, CA
    Posts
    620

    Default

    Quote Originally Posted by Mac View Post
    Final update, I hope!

    I relubricated the worm drive of the read/write head, and now it reads and formats disks no problem.
    I still need to source some more DD floppies though. Anyone know of any European shops selling them? I'd like to avoid the shipping hassle of ordering from floppydisk.com.
    I believe Stone sells floppies, maybe check with him. Otherwise eBay. Luckily 3.5 are pretty common and I've never had a problem using 1.44 with the left hole covered (electrical tape works well).

    Avoid colored disks
    -- Brian

    Working Systems: Apple IIe/II+/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, TRS-80 Model 4 GA
    Project Systems: Amstrad PCW 8256, Kaypro 2/84 (Bad Chips: 81-194, 81-189).

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •