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Thread: Shugart 851 vs YE-DATA 180

  1. #1

    Default Shugart 851 vs YE-DATA 180

    I used to use a Shugart 851 to read RX02 disks using the Catweasel. I also have the DBIT FDADAP to convert to a handle the TG43 signal.
    This has been working very well.

    For some reason I though I should replace the big Shugart with a slim YE-DATA 180, mostly because it happen to come in a nice pre made cabinet (marked Regnecentralen AS). It didn't turn out well at all!

    Why? Right after track 43 it goes bad. So it has something to do with the TG43 signal. Apparently the YE-DATA has something called Switch Filter which also use the TG43 signal (but then assumes it to be active on tracks 60 to 76). There is also a jumper to control this. It is marginally better to have this jumper out than in. When out it is able to recover a few sectors on each track. When in no sectors are recovered on tracks greater than 43.

    My though was that TG43 was only for writing but apparently the YE-DATA drive does something more here.

    It could also be that the disks are bad. I haven't tested them in a real RX02 yet, neither in the Shugart 851.

    Opinions? Disks bad or drive weird?

    To confirm a difference I need to bring the good old Shugart 851 back into operation. Unfortunately it is in storage now.

  2. #2
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    Quote Originally Posted by MattisLind View Post
    I used to use a Shugart 851 to read RX02 disks using the Catweasel
    This has been working very well.
    Stick with the 851, the heads are easy to clean once you take the plastic shield off and you'll read in
    a bunch of places here how the half-height YE-DATA/Qume drives are media-eating pieces of junk.

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    I've always steered away from half-height 8" drives. Most are inferior to the full-height versions.

  4. #4

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    I’ve actually had good luck with four HH Qume drives I use, both at SD and DD. The one issue I have had is drive interchange when used in a hard sector format, but that’s because index alignment cannot be adjusted on these drives. This, however, is not the problem the original poster is encountering.

    The other major difference in my success with the drives is that most of the media was written on these drives, though some recovery was done from original Vector Graphic disks from the very early 80’s.

    This being said, the HH drives do feel and sound like junk compared to the full height drives.

    Mike

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    On the YD180, you should still be able to read 43-59, regardless of the TG43 signal, as it's not supposed to kick in on reading until track 60. Have you checked your drive alignment? That sounds more like the problem you're having.

    I'm going from the Qume 242 manual, which I believe is the same as the YD 180.

  6. #6

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    Quote Originally Posted by Chuck(G) View Post
    On the YD180, you should still be able to read 43-59, regardless of the TG43 signal, as it's not supposed to kick in on reading until track 60. Have you checked your drive alignment? That sounds more like the problem you're having.

    I'm going from the Qume 242 manual, which I believe is the same as the YD 180.
    If you read page 9 on section "Low current / Switch Filter" you see that the TG43 is supposed to be active from track 60 to track 76. So the TG43 signal has effect. But on the other hand then the SF jumper possibly would negate it. It is little bit tricky from the manual to find out ifthe Switch Filter is active when it is inserted of removed. However it was worse when it was inserted.

    It could be that the media was not happy to be written with low current once upon a time. I am not entirely sure how the original RX02 which once wrote the disk deal with TG43. Does it lower write current or not? But I assume it does.

    Could be alignment problem. But why does it occur exactly on track 44 and onwards. Track 43 reads perfectly.

    I will try with a real RX02 and a Shugart 851 to see if they could be read. They shall contain the Dilog DQ604 formatter program which I like to recover. I have scanned the manual already.

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    Essentially what I said in your quote of mine. You should be able to read 43-59 without the TG43 signal.

    There are some drives that don't care about this signal--they're smart enough to count the cylinders themselves.

  8. #8

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    I maybe is misunderstanding someting? Isn't the DBIT FDADAP setting TG43 active at track 44 and higher regardless of read or write. I thought so. Cannot see evidence that it does something special for read.

    Then I will get the FilterSwitch condition earlier than expected, right?
    Last edited by MattisLind; July 7th, 2018 at 01:36 PM. Reason: Misreading

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    Yes, you can ask John Wilson, but I believe that the FDADAP simply counts steps (forward and reverse) and asserts TG43 a the right time. But as I mentioned, some drives don't need the signal.

    If I read the OEM manual for the 242YD180, asserting TG43 at cylinder 60 on reading is supposed to help. I'm not sure how many implementations actually do that. I'll add that the 242/180 are not my favorite drives; the full-height Qume drives (e.g. DT/, in my experience are quite a bit better. On my list, I'd say the Shugart comes first, followed by Siemens and then Qume and the rest of the lot--all full-height drives.

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