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Thread: Tandon Maintenance

  1. #1
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    Default Tandon Maintenance

    [NOTICE: FEEL FREE TO SKIP THIS PART]

    Thanks to Modem7 for pointing out Tezza's alignment procedure, to Chuck(G) for the link to the Tandon maintenance manual, to Al Kossow for maintaining it, to Jafir for the solution to the SS SYS problem, which I have also encountered, and to Stone - you are surprised?

    Rather than divert the previous thread concerning formatting a SSDD disk I would like to ask a few specific questions about Tandon maintenance, as I have 4 TM100-2 or 2As and one TM100-4 that all have indicated a one problem or another and been replaced with "one that works" in a 5160 or a 5170 or a lowly Kaypro. As my understanding has progressed I have been able to better understand the nature of the issues, which break down into groups: operator error, electrical problem, mechanical problem.

    Operator error, - jumpers in the wrong place, missing terminal resistors or resistors where they don't belong, etc. I've asked a lot of questions about that in the past and I think I understand that subject well enough to catch the most egregious.
    Electrical problem - on the advice of the majority I now just assume that if it's electrolytic I should replace it, but if caps don't fix it I can't fix it. Given the absence of operator error most of the rest of the electronics are assumed to be bulletproof.
    Mechanical problem - cleaning and lubrication top the list. Making sure everything moves freely is the first step. As Chuck points out most alignment issues are really Track0 sensor issues.

    [OKAY, THE POINT OF THE POST]

    Having gone through these Tandons to make sure they are configured properly, they are clean and move freely through the range of motion and that any electrolytics have been replaced, I now face one more issue, common to all. I am using a SuperCard Pro as my drive exerciser. The SCP software has a suite of drive utilities; maximum track test, drive speed test, alignment test and media test. The Tandons pass all these tests except the media test, which writes to T0H0, T0H1, T1H0, T1H1, etc. sequentially, and reports success or failure of the write-read combination. The Tandons all report multiple failures of H1. H0, which I believe is the bottom one, is fixed. H1 is suspended above and has some "wiggle room".

    I don't know whether the disk is moving (not securely clamped in place) or the head is moving (not aligned properly) or simply not making good contact with the media surface. I've tried this test with multiple disks and it recurs in the same pattern.

    So the question is: Does anyone have a suggestion for how to diagnose further? What to look for? I do have a dual-channel scope and a 5.25 alignment disk and thanks to the above contributors, some idea how to proceed.

    Thanks for your replies,

    -CH-

  2. #2

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    Quote Originally Posted by clh333 View Post
    I don't know whether the disk is moving (not securely clamped in place) or the head is moving (not aligned properly) or simply not making good contact with the media surface. I've tried this test with multiple disks and it recurs in the same pattern.

    So the question is: Does anyone have a suggestion for how to diagnose further? What to look for? I do have a dual-channel scope and a 5.25 alignment disk and thanks to the above contributors, some idea how to proceed.
    CheckIt has a Mini-Spiral Disk that it employs via its software to test the following:

    Alignment
    Clamping
    Hysteresis
    Speed
    Track 0

    I have used this method successfully and am quite satisfied with its results.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  3. #3
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    Default

    Charles,
    I'm curious if this same problem exists with a couple different Manufacture's Floppy Drives?
    It's possible Jim could have a Software problem with the tests. I don't remember testing
    testing any floppy's with my Super Card Pro. And I haven't a clue as to which Brand of
    Floppy or Diskette's I used.

    When I aligned the Floppy's I used different Software, but once again I forget what it was.
    It seems to me it was a Floppy that Tandy used in their Alignment, but it's been too long.
    There is some Diagnostic Software on the Humongous CP/M site. And I may may have some
    in my stash of Radio Shack Software. I'll search through the listing I have.

    I'd suggest trying a couple different Brand Floppy Drives to see if they have the same type problems.
    If you can adjust the stepping rate in the Supercard Pro software, you might try that as it could be
    the problem.

    Larry

  4. #4
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    Default

    Quote Originally Posted by Stone View Post
    CheckIt has a Mini-Spiral Disk that it employs via its software to test the following:

    Alignment
    Clamping
    Hysteresis
    Speed
    Track 0

    I have used this method successfully and am quite satisfied with its results.
    What version might be used with a machine that can talk to a TM100-2? Is the Mini-Spiral disk still available as a 5.25" or does the program create one on the fly? (I'd like to see that, if so.)

    Thanks,

    -CH-

  5. #5
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    Default

    Quote Originally Posted by ldkraemer View Post
    Charles,
    I'm curious if this same problem exists with a couple different Manufacture's Floppy Drives?
    It's possible Jim could have a Software problem with the tests. I don't remember testing
    testing any floppy's with my Super Card Pro. And I haven't a clue as to which Brand of
    Floppy or Diskette's I used.

    When I aligned the Floppy's I used different Software, but once again I forget what it was.
    It seems to me it was a Floppy that Tandy used in their Alignment, but it's been too long.
    There is some Diagnostic Software on the Humongous CP/M site. And I may may have some
    in my stash of Radio Shack Software. I'll search through the listing I have.

    I'd suggest trying a couple different Brand Floppy Drives to see if they have the same type problems.
    If you can adjust the stepping rate in the Supercard Pro software, you might try that as it could be
    the problem.

    Larry
    Yes, it's possible this is an artifact of the SCP. I'd rather investigate every other possibility before bringing the subject up with Jim, however. I did try different brands of disks as well.

    You would think that the fact that H0 is relatively reliable and H1 is not would eliminate any timing issues but I suppose it is possible that while the drive is trying to transmit its H1 read it is also initiating a step (forward) and the motor actuation is enough to cause a problem with the transmitted data. How that is handled is beyond my meagre knowledge.

    -CH-

  6. #6

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    Quote Originally Posted by clh333 View Post
    What version might be used with a machine that can talk to a TM100-2? Is the Mini-Spiral disk still available as a 5.25" or does the program create one on the fly? (I'd like to see that, if so.)
    There is no version.

    DOS can't read the disk natively. It can only be effectively used from CheckIt or its included executable, CHECKFD.EXE.

    It doesn't appear to be available either new or otherwise. The Mini-Spiral Disk is from Touchstone Software Corporation and was manufactured by ASKY, Inc.

    If there were a way to reproduce it I would gladly make one for you.
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  7. #7
    Join Date
    Sep 2012
    Location
    Indiana, USA
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    511

    Default

    I would like to recommend an extra step to the cleaning/lubricating regime for Tandon drives. I always let some light oil soak into the stepper motor around the spindle. Set the drive on it's side and apply a small amount of light oil, or even WD40, around the spindle. Let it rest awhile, then put the drive on it's opposite side and repeat the procedure on the other side of the stepper. I have had this correct unreliable drive operation more than once.

  8. #8

    Default

    Part of my first cleaning process on these Tandon 100-2A drives that are mis-behaving is to remove all connectors from the top and rear PCB's and give the pins a good clean and make sure the connectors are a tight fit when re-fitting, I've gotten a few of these drives back in the land of the living just by cleaning the pins as they can go tarnished over time.

  9. #9
    Join Date
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    Cleveland, OH, USA
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    Thank you fatwizard and Malc for your suggestions. I have been incorporating them as part of my cleaning routine. The first time I put WD-40 on a stepper motor shaft I wondered if I was nuts, but I immediately felt the shaft free up, and when I found the motor still operated I felt like Columbus discovering America. Or something.

    The only connections I haven't touched are the ones at the upper head, and I've been wondering if oxidation is the culprit there. So far I haven't had the guts to pull one, but there may come a day...

    -CH-

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