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Thread: Aligning Floppy Drives

  1. #1

    Default Aligning Floppy Drives

    Hello All,

    Recently I have purchased a number of 8" drives in unknown states. I've managed to clean them up and make sure they run and so far good. Now, I'd like to align the drives properly and I am coming looking for tips and hints. For my 3 1/2" and 5 1/4" drives I use HRD disks from Accurite but they had stopped selling HRD disks for 8" drives (as well as HD 5 1/4" drives) a while back. So the only solution seems to be AAD disks now. So here are my questions that I am hoping the hive mind can help me with:

    1. Is Accurite still in business? I have emailed and called them over the past week and I have not gotten any response. Does anyone know if they are still in business and selling floppy test equipment?

    2. Assuming they are still in business and I purchase an AAD from them my understanding is that I need an oscilloscope to properly use AAD. How hard would that be for a guy who has never used a scope? Is it pretty straight forward or do I need a degree in EE?

    3. Finally, I need a scope. I never (probably) have use for a scope out side of this one specific task. Having said that my budget for a scope is "limited". I was checking around and I saw a number of USB scopes where I assume it is a DAC connected to probes and all the muscle is in SW on the PC. Say something like this. Would this work? Or would I need something more powerful (i.e. expensive)?

    4. Any alternatives I should be considering?

    Thanks!
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  2. #2
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    Personally, for 8" drives, I'd recommend a digital alignment floppy, if you can find one. It's much easier to use than an AAD (a DSO if you do decide to use the AAD is definitely preferable to a plain old analog scope) and the results can be very good.

    I've heard that recently, Accurite hasn't responded to emails nor had anything but a recorded message, so it's hard to say if they're still in operation.

  3. #3

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    [QUOTE=Chuck(G);360193]I'd recommend a digital alignment floppy, if you can find one.[/QUOTE

    That is a big if. I was able to get the HRD disks for 3.5" and 5.25" drives from another VCF member here. Even back then Accurite seemed to be just selling old stock.

    Quote Originally Posted by Chuck(G) View Post
    a DSO if you do decide to use the AAD is definitely preferable to a plain old analog scope
    I would have thought any of the cheap "new" scopes on eBay from China would be DSO and not analog? I guess the real questions for me would be how many 1. channels would I need and 2. what freq. response if all I am concerned with is aligning disks. Since the signal should be repetitive the real time sampling doesn't need to be that high. I am guessing just about anything "should work" but want to be positive my $45 no name scope off of eBay will do the job. Or in other words I do not want to end up needing to buy a $1000 (or more) scope just to align a few drives.

    Quote Originally Posted by Chuck(G) View Post
    I've heard that recently, Accurite hasn't responded to emails nor had anything but a recorded message, so it's hard to say if they're still in operation.
    Well I am hoping they are still around enough to sell off old stock. I will try more this week before declaring it a lost cause.

    Thanks!
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

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    The cheap Chinese scopes are certainly DSOs. I was trying to warn you away from the older used analog scopes. Wonderful things in their own right, but very difficult to use to align a drive, mostly due to the fact that a 360 RPM 8" drive produces data at 6 times per second, which is hard to see on an analog scope, unless less it's a storage model--and that has its own problems.

    I suspect that if Accurite doesn't come through, some enterprising soul could come up with a means of creating alignment disks. For example, one could tinker with the clamping setup so that a disk was clamped slightly off-center. Write a track full of sectors, put the disk in a known calibrated drive and note which sectors are readable. What you'll get is a pattern of not-readable, followed by a string of readable sectors, followed by more unreadable ones. So to align a drive one would set the drive to display the same string of readable sectors.

    Floppies aren't rocket science.

  5. #5

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    Quote Originally Posted by Chuck(G) View Post
    The cheap Chinese scopes are certainly DSOs.
    Any "brand" you would recommend?

    Quote Originally Posted by Chuck(G) View Post
    I suspect that if Accurite doesn't come through, some enterprising soul could come up with a means of creating alignment disks.
    Maybe. More then likely an enterprising soul will offer the service for a price. Which is fine if my sole purpose was to get a drive up and running. However, since I want to learn about maintaining the drives and how they work being hands on is always better. To me that is part of what makes this a hobby. Of course if someone does start producing alignment disks well my hats off to them and a thousand blessings upon them

    Quote Originally Posted by Chuck(G) View Post
    Floppies aren't rocket science.
    I suspect that is true for most endeavors (the one exception of course being rocket science - fortunately I have a huge number of the practitioners of that art located a stone throw from me) if you know what you are doing. If not, well it may as well be brain surgery and not rocket science .
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

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    Quote Originally Posted by Shadow Lord View Post
    Any "brand" you would recommend?
    Other than "kick the tires" experience with Rigol, which are actulally pretty decent, I can't opine much on the subject. However, an interesting option is that Keysight (used to be Agilent, used to be HP) has announced a line of economy scopes. Don't know a thing about them, though.

    There are also USB oscopes which I have no experince with, but I'd expect them to be much less expensive that the "real ones with a screen" type.

  7. #7

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    So I heard back from Accurite. They are still in business. Unfortunately they do not have HRD disks anymore nor do they sell Drive Probe. They do however still sell AAD disks here. Unfortunately, looking at that table I am not sure what to order if my main interest is in aligning "standard" IBM PC compatible drives (5.25" 360KB and 1.2MB, 3.5" 720KB, 1.44MB, 2.88MB, and 8" MFM DS drives)? Any ideas/help? Thanks.
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  8. #8
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    It's quite possible to do a functional alignment on an 8" drive using a known-good floppy. Just run a READ-ID utility in a loop and see the extent where sector ID's disappear either way, then set your permanent position in the center.

    Since the ever-present Tandon TM-100 interests people the most and also tends to go out of alignment, I'd probably start there.

    3.5" drives have a 135 tpi track density; given their small size, aligning those can be a pretty twitchy affair. On the other hand, they tend to lose alignment less easily than their larger cousins.

  9. #9

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    Quote Originally Posted by Chuck(G) View Post
    Since the ever-present Tandon TM-100 interests people the most and also tends to go out of alignment, I'd probably start there.
    But with which disk? For example the site lists the following:

    AAD Model Drive Type/ Size Radial Tracks Index Burst Tracks Azimuth Burst Tracks
    208-40 Note A 5.25" 360 Kb 16 1, 16, 34 16
    208-41 Note A, B 5.25" 360 Kb 0, 16, 39 0, 16, 39 16
    224/2A 5.25" 360 Kb 16 1 & 34 34

    Note A - Dynamic AAD. Simultaneous monitoring and adjustment of radial alignment, azimuth rotation, and index timing patterns without repositioning the drive head.
    Note B - Multiple radial patterns occur on side 0 only. A single radial pattern occurs at the center radial position on side 1
    So to my untrained eye all the disks seem to support the TM-100 and disk 208-41 seems to be the best because it has three tracks that can be used for alignment vs. one on side 0. Side 1 apparently on all three disks has just an alignment track on track 16 (if I am reading the table correctly). Is there a situation in which having multiple tracks is not good?

    Things get even more confusing for me in the 8" territory as the specs are the same on the chart but according to Accurite the "timing is different". I noticed that the model numbers seem to match Dysan model numbers in some parts. Was there a standard cross reference between drives and models of alignment disks?

    The Qume 842 service manual lists a Dysan and a Dymek alignment disk as available for order unfortunately it uses Qumes internal part number...
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  10. #10
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    Well, I'll have to check my stock of Dysan 8" alignment disks to see what's what. But I'm currently with you that the 208-41 looks to be the best bet.

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