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Weird Old Hardware Question -- Failed Disks with Scratched Out Magnetic Rings...


DavidD

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Okay, this question is years old, and I've always been curious about it.

 

Way back when, I received an XF551 for my XE Game System... that, and the 850 I got for free, gave me a full working computer!  (State of the art for the early 90s, of course. Cough. Cough cough.)

 

I remember having several issues with the XF551, though -- I remember reading something about it having weak solder on the cable connectors, but that wasn't the problem...

 

On several of the older commercial disks I received, the disks ended up... weirdly scratched.  Clear rings appeared on the disks.  Something was scratching off the  magnetic coating when the disks spun... this didn't happen in most cases, but it did in a few.  (Poor, poor Way Out).

 

My question is -- what would have been the most likely culprit?  Old disks with weak magnetic material?  Dust getting stuck on the disk and dragged by the drive itself?  A bad drive mechanism?

 

This was ages ago, and I got "new" XF551 drives afterwards, and the older one (which stopped working) was fixed...

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If it is only on some disks, but others work fine, and it doesn't seem to "infect" new disks, there is a good chance that some grit got stuck in the liner of the plastic disk envelopes of the bad disks.  

If new disks get damaged, then it is likely the drive.  If it is the top/label side of the disk that gets damaged, there may be some grit in the rabbit fur pad that presses on the top of the disk.  If it is the data side ("bottom") of the disk, then your head may be dirty.

 

I clean my drives using a Q-tip with denatured alcohol. 

 

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I found that certain makes of disks don't age very well especially is they've been stored in damp

conditions, these disks seem to lose the adhesion of the magnetic material to the plastic

of the floppy and the pressure of the head is enough to remove the coating and in the process

leaving loads of material on the head which then needs cleaning.

 

One this happens, the disks are useless

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anytime you see a 'ring' lightly or grand canyon style showing on a disk.... Brush the rabbit and clean the heads!

Take the disk and carefully whacking it about without touching the media, aerodusting debri out and then cleaning the media.... once done and dry... using a clean double headed drive, make a back up copy... Kry/SCP/vapi/atx/atr whatever works best for you..

If only using Atari drives, use a quality sector editor and or bitwriter/happy/archiver drives and their software.

You are looking to get the data in go, that is as fast a possible without going over the damaged part more than once.

After you grab the initial data, you can go back and read the bad spots a few times and see what you can recover. Always clean the drive again after your done...

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What were the other titles that were damaged?  I have this short list of disks that the XF551 has been known to damage in the way you describe, supposedly due to the XF551 spinning at 300 rpm (not that this reasoning makes sense to me!):

      - Flight Simulator II (subLOGIC)
      - Blue Max (Synapse) (I have personally destroyed multiple Blue Max disks with the XF551 drive!  -mc)
      - Bank Street Writer (Broderbund).  Conflicting reports about this one.
      - Boulder Dash II (Databyte release?)
      - Inside (Spektra, 1990?--original Polish version?)

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11 hours ago, hunmanik said:

What were the other titles that were damaged?  I have this short list of disks that the XF551 has been known to damage in the way you describe, supposedly due to the XF551 spinning at 300 rpm (not that this reasoning makes sense to me!):

      - Flight Simulator II (subLOGIC)
      - Blue Max (Synapse) (I have personally destroyed multiple Blue Max disks with the XF551 drive!  -mc)
      - Bank Street Writer (Broderbund).  Conflicting reports about this one.
      - Boulder Dash II (Databyte release?)
      - Inside (Spektra, 1990?--original Polish version?)

This was years ago, so I don't quite recall.  However, when I dig out my bag of disks, I'll check.

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15 hours ago, hunmanik said:

What were the other titles that were damaged?  I have this short list of disks that the XF551 has been known to damage in the way you describe, supposedly due to the XF551 spinning at 300 rpm (not that this reasoning makes sense to me!):

      - Flight Simulator II (subLOGIC)
      - Blue Max (Synapse) (I have personally destroyed multiple Blue Max disks with the XF551 drive!  -mc)
 ...

 

This doesn't have much to do with the specific drive. Some drives do are slightly worse than others depending on the pressure exerted by the heads. But it mostly depends on the media much more than the drive. Most Synapse disks of the period are known to be extremely fragile and they could be destroyed by being read (actually, just by rotating with the head engaged) in any drive including an 810 or 1050. Blue Max and Zepellin are probably the worst titles, in this sense.

 

Quote

With that reasonong all 3.5 drives with their 360rpm would be real diskette killers.

 

Just for the record, 3.5" drives, at least normal PC ones, rotate at 300 RPM, not at 360 RPM.

Edited by ijor
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I see in the 810 FSM there is this spec: Pad Pressure = 17 Grams.  Would this be the pressure exerted by the heads?  

 

I don't see a comparable spec in the 1050 FSM.

 

But if this is the relevant spec, maybe it is a bit different/more for the XF551?

 

My experience with Blue Max disks on my XF551 was just like the op described with Wayout - the drive seemed to literally scrape the media off of the disk, creating a narrow ring where you could see right through the disk.  The result was identical (same location on the disks) with two Blue Max disks that were both fine when used on an 810 but ruined by the XF551, but the XF551 never did that to any other disk.

 

I have seen scattered reports of similar experiences with the XF551 over the years, so that's why I suspect it's a result of something different about the XF551 compared to other Atari drives, even if the pre-existing condition/quality of certain disks is the bigger factor.

 

 

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