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Thread: SFD-1001 troubleshooting help needed

  1. Default SFD-1001 troubleshooting help needed

    Hi VC!

    I have a SFD-1001 drive that's been in a broken state for too long, so today i started troubleshooting it. The original problem was that it flashed six times at startup. I found some info online saying that six flashes either meant that the 6530 or one of the 6502's that was broken.

    The 6530 is on a break-out board together with a 2716 eprom (which i read came from commodore re-using old stocks of 6530's with the wrong data burned into the ROM part of the 6530).

    Rumors online says that the 6530 often is faulty on the SFD-1001, so i started there. In with a replacement 6530 and.. six flashes.

    I downloaded the floppy disk controller ROM from zimmers.net, dumped the 2716 EPROM and compared the bin files. Equal match.

    Switched the two 6502's around and.. constant red light from the LED. We're onto something here...

    I replaced one of the 6502's and the drive gave me a green light.

    The trouble now is that when i format a disk, i can hear the drive step ~20 times, and then it starts to click, and the drive keeps spinning for a while and then stops. When i read ds$ i get 20,read error,97,18,00. (i assume the numbers mean something here, and may give someone who knows things about stuff a clue)

    So this is where i'm stuck. Any help appreciated.
    //RS

  2. #2

    Default

    My SFD-1001 needed a full recap, not anything related to the main PCB; but the motor PCB itself, a tricky and nasty job. I replaced all caps, most of them leaking and with corroded tracks around and after a lot of fixes, it worked again
    No idea if it's a known weakness of this drive; but it's worth to try to examine the caps status...

  3. #3

    Default

    I have a thread about IEEE drive blink codes, as opposed to other types of drives. The SFD-1001 is a single-drive equivalent to the 8250 and from the following sources 6 blinks indicates a bad 2114 RAM in the 1000h-13FFh memory space.

    http://vintagecomputer.net/browse_thread.cfm?id=301

    6 blink means you have an issue with the Common RAM $1000-$13FF 2114 UC4,UC5

    It could be a filter cap or related component in the circuit, or the 2114 RAM chip itself.

    Bill
    @ BillDeg:
    Web: vintagecomputer.net
    Twitter: @billdeg
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  4. Default

    Thanks for your help so far.

    I've re-capped the board on the drive. Now when i try to format i get FORMAT SPEED ERROR, which i'm guessing is due to the re-cap. So i'm guessing that the speed needs to be calibrated somehow. Does anyone know how to set the speed?

    What should i use for reference when calibrating? Will the index hole sensor do?

    I've never done this kind of calibration before, so any "best practise" info is appreciated.

    PS. I may have gotten 5 flashes before, not 6. I'm sure that when i looked it up, it said that the 6530 or a CPU could be the problem. And since replacing a faulty 6502, the error codes has disappeared.

    //RS

  5. #5

    Default

    this is good. now you only have to adjust to 300 rpm and you're probably very close if nothing else is wrong. do you have any way to load programs onto the computer other than this sfd-1001? 8050? If so, you can download a program off my web site (not sure what kind of system you're running) that will tell you your RPMs (for an 8250 drive). With this knowledge there is a potentiometer on the drive control board that you can use to make the adjustments. tiny adjustments. re-run the test again. If you're off another tiny adjustment, etc. Works great. problem is the programs I have are for the B Series commodores mostly so if you're using something else you'll have to find the equivalent. otherwise you'll have to adjust blind.

    If all you have is the sfd-1001, you can tell it to be a "8050" with basic commands. Hopefully you can at least load programs.

    What happens if you enter the command ?DS$

    here is a program I use to test RPM
    http://vintagecomputer.net/commodore...EST8050FMT.D80

    if you have some other combo system/drive you may have to find the compatible equivalent.

    1. load program on working drive as drive 8 (or 9 if you can)
    2. power off working drive, power on sfd-1001 leaving computer running
    3. run RPM test
    4. adjust drive
    5. repeat test until ~300 is reading
    6. attempt a format:
    header "disknamehere", d0, i01

    I forgot...if you can't load a RPM program, you can always make little adjustments, very little, and blindly adjust the RPMs. I am talking 1/8 turn counter clockwise or counter-clockwise might add/remove 5 RPM. You want to make clear note where you started, and you should not have to turn more than 1/3 way around either direction TOTAL.

    b
    Last edited by billdeg; February 9th, 2016 at 04:07 AM.
    @ BillDeg:
    Web: vintagecomputer.net
    Twitter: @billdeg
    Youtube: @billdeg
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  6. #6
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    Default

    If you can't find/load a suitable program, you can use one of these.

    http://www.ebay.co.uk/itm/391364439621

    At less that 10, a bargain if you're going to do more work like this in the future.

  7. #7
    Join Date
    Oct 2011
    Location
    Cwmbran, Wales, United Kingdom
    Posts
    483

    Default

    Quote Originally Posted by crock View Post
    If you can't find/load a suitable program, you can use one of these.

    http://www.ebay.co.uk/itm/391364439621

    At less that 10, a bargain if you're going to do more work like this in the future.
    Knowing RetroSweden he'll love that - a new gadget. Expecting him to only order one is ridiculous though!

  8. #8

    Default

    Thanks for a very informative reply!

    Quote Originally Posted by billdeg View Post
    this is good. now you only have to adjust to 300 rpm and you're probably very close if nothing else is wrong. do you have any way to load programs onto the computer other than this sfd-1001?
    I've been using a bitfixers PETdisk during my test now.

    Quote Originally Posted by billdeg View Post
    If so, you can download a program off my web site (not sure what kind of system you're running) that will tell you your RPMs (for an 8250 drive). With this knowledge there is a potentiometer on the drive control board that you can use to make the adjustments.
    Is this the potentiometer that you're referring to?
    http://imgur.com/aY03WO0

    Quote Originally Posted by billdeg View Post
    problem is the programs I have are for the B Series commodores mostly so if you're using something else you'll have to find the equivalent. otherwise you'll have to adjust blind.
    I replaced my test machine, an 8032, with a B610 in order to avoid having to do it blindly.

    Quote Originally Posted by billdeg View Post
    What happens if you enter the command ?DS$
    i'm getting 75, format speed error.

    Quote Originally Posted by billdeg View Post
    here is a program I use to test RPM
    http://vintagecomputer.net/commodore...EST8050FMT.D80
    Should the program name be "RPM test"? I couldn't find one with that name on the disk image, so tried the "Performance test" program.
    however i couldn't see anything resembling an RPM measurement.
    http://imgur.com/QVJuJqK

    I also tried the CBUG#83 "speed test" program. However i got "Error # 2 on job # 176". I have no idea what this means.

    //RS

  9. #9

    Default

    Quote Originally Posted by crock View Post
    If you can't find/load a suitable program, you can use one of these.

    http://www.ebay.co.uk/itm/391364439621

    At less that 10, a bargain if you're going to do more work like this in the future.
    Thanks. That's not a bad deal with the free shipping. I ordered one "just in case"

    //RS

  10. #10

    Default

    Yes, that I believe is the correct potentiometer. If you have a 610 you can use most all of the programs from my web site for B series and 8250, or you can run the program to tell your sdf-1001 to think temporarily it's a 8050 to load those programs into memory, then swap back to test.

    One other thing. There are many programs, one will work for you, but not all.

    Bill
    Last edited by billdeg; February 11th, 2016 at 06:37 PM.
    @ BillDeg:
    Web: vintagecomputer.net
    Twitter: @billdeg
    Youtube: @billdeg
    Unauthorized Bio

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