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Thread: SFD-1001 inconsistent

  1. #1

    Default SFD-1001 inconsistent

    So recently I got my SFD going in single sided mode (see other thread). Seemed to work well. I am able to format and read disks in single sided mode. I started to create some D80 images on my PC to transfer to my SFD via Zoomfloppy and CBMTools. I started by formatting a disk using CBMXfer, all good, then I sent the image to the SFD. It started to write the image then at about track 9 or 10 it started to give me read errors. I stopped the process and then used imgcopy.exe to send the image from the command prompt. That worked. I then created a new image and tried to write that, the same way. But again, it started to give me read errors at about track 23. I then tried to use D82Copy.exe, same thing. After trying a few things, reformatting the disk etc... it just happened to work. But then I started having issues reading the directory. So I move the SFD back to my C128 and started to have the same issues there. After resetting the drive and the computer a couple of times it started to work again.

    I did not see these issues when I was troubleshooting before, but of course I was not reading/writing as much.

    I'm not sure where to look for this one. It's just so inconsistent.

    BTW - The images I created and successfully transferred to floppy work well, when the drive is working. But just yesterday I tried to load the directory of one just to test is it took about 4 - 5 resets/reboots before it started working and then was fine.

  2. #2

    Default

    Hi,
    you should really read the error channel. The actual error matters a lot.
    Most half-height mechanics used by CBM develop contact problems on the media surface. The top head's can't make a good pressure on the media so even the bottom head can't touch the media properly (since the disk surface isn't pressed enough evenly to the bottom head).
    It happens because the head lifting mechanism works only on the left side of the head. This can be usually solved by gently twisting counter-clockwise the top head (very gently!) with disk inserted and door closed.
    However my experience is ONLY with 48 TPI mechanics, the SFD-1001 has a 100 tpi mechanics, so it might be not related to this kind of problems.
    You have to read the error channel and let us know what it says.

    Frank IZ8DWF

  3. #3

    Default

    I'll see what I can get. BTW - I am using 1S/4D 96tpi floppies. But it was happening to my 2S/2D 48tpi disks as well.

    Thanks!

  4. #4

    Default

    Quote Originally Posted by Digitalman View Post
    I'll see what I can get. BTW - I am using 1S/4D 96tpi floppies. But it was happening to my 2S/2D 48tpi disks as well.

    Thanks!
    4D 96tpi or 2D 48tpi use exactly the same magnetic media, see:

    http://www.retrotechnology.com/herbs_stuff/drive.html

    (HD 96tpi media, on the other hand, isn't compatible with either the old 96/100tpi "4D" drives or the 48tpi 1D/2D drives).

    The 4D 96tpi disks were just a bit better quality-wise.
    In the early '90s we used to test various brands of 2D and 4D (not HD) media to be used on the Olivetti LSX-3005 720K 5.25" (96tpi) drives and basicly the better yield were with 48tpi Olivetti branded floppies and 3M 48tpi floppies. Most of the other brands worked almost as well, with some occasional bad sector after some use. I think the cheaper brands were just "less tested", not much better quality.
    Frank

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