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Thread: Aligning Floppy Drives

  1. #61
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  2. #62
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    Quote Originally Posted by inotarobot View Post
    Interesting machine. So little info about it comes upon a Google search. Guess it was a special made using a modified Olivetti PC machine ?
    No, it does not need a PC. It's standalone.

  3. #63
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    Helpful thanks.

  4. #64
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    This is an interesting brief manual for the DYMEK alignment disks.

    I dont see it on BITSAVERS so maybe it could be added at some point.

    http://www.myatari.com/dymekalign.pdf

  5. #65
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    Question Flpppy Drive alignment

    I am wondering if the Moderator would consider moving this whole post across to a different forum section since many different machines have floppy drives, not just "PC's and Clones"

    May I suggest the area "General Vintage Computer Discussions" as it covers the area of "restoring" as well?,

    or even the "Other" section in the "GENRES" section of the Forum.

  6. #66

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    Hey Chuck.

    I am trying to get started doing an alignment on a Shugart SA400. I have the SA400 manual, and I have two Shugart SA400s. One seems to be out of alignment, but will read and write a disk, but only disk that were created by itself. It will not read disks that are created by any other drives.

    I have a scope and a dysan 224/2A alignment disk. I would like to make a video going over the each step and scope settings, to help others who find themselves in the same position. The only video I found was a very old 80's radio shack video, that does not provide the details that are needed to do an alignments by yourself.

    I am not an experienced electronics tech. So my scope skills are remedial, so I need to verify that I am setting up the scope correctly, to get the correct readings. So, that I can compare them to the bad drives settings.

    I am currently using a SOL-20 with a N* MDS-AD3. I have downloaded Mike Douglas and Martin Eberhard's NODDEXER.COM and have been familiarizing myself with this utility. I also have an Altair, and the AFEXER.HEX utility,which might be something that you maybe more familiar with.

    Attachment 55490 Attachment 55492 Attachment 55493
    Attachment 55485 Attachment 55486 Attachment 55487 Attachment 55488 Attachment 55489

    I would like to make sure my Scope is setup correctly, and I would like to know how I am supposed to "Write the entire track with all one's" as directed.
    I would appreciate any help you are able to give me.
    Last edited by Novell2NT; August 25th, 2019 at 09:22 AM.

  7. #67
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    With your alignment diskette, you should be looking at section 2.3.11, 2.3.15 and 2.3.18 of the service manual in that order.

    If the spindle isn't turning at more or less exactly 300 RPM, you will still be able to read and write your own floppies, but nobody else's. Thus, 2.3.11. The motor setup on the SA400 is a bit sloppy and can drift with time. You don't need a frequency counter--a simple neon "night light" should allow the strobe pattern on the spindle target to show. You can also use a formatted disk and IMD to verify the drive RPM.

    While the track 0 sensor shouldn't change position under normal circumstances, it might have been tinkered with. (Do you know where your drive's been?) Still worth checking per 2.3.15.

    Finally, the SA400 uses a primitive "spiral groove on a plate with follower" scheme. Unless the misalignment is due to wear of the groove (it will never hold alignment in that case), you can use 2.3.18 and your scope to check that with your alignment pattern with your alignment disk. (You should never ever write to that disk; to do so renders it as junk).

    Hope this helps.

  8. #68
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    IMD. image disk program has a analysing tool in it.

    I use it also for 8".
    You can attach the drive to a PC dos or win computer.
    With several known good FFDs you can observe per track sector if data is allined.
    That through the nummeric field.

    Great tool.

  9. #69

  10. #70

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    As an added protection, you should put a piece of tape over the write gate finger. You can put a piece of clear tape over several fingers and then cut, with a razor blade or exacto, the tape on either side of the finger you wish to cover. If you allow the tape to continue all the way to the edge of the board, over to the beveled edge. it won't get rubbed off when you slide it into the connector. Remove the excess tape. This well ensure that you won't write to the disk.
    It is also a useful trick when you are doing debug, for some other edge connector, and you want to block some signal.
    Dwight

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