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I have probably ~200 DC600A quarter-inch cartridge backup tapes from the late 80s and early-mid 90s. I have 2 drives that are capable of reading DC600A tapes, but the drives were destroying tapes. At first, I thought it was a problem with both drives, but after many tens of hours of investigation, I am now certain that the rubber tension band in each of the DC600A cartridges is so weak from aging that they are snapping (which then often ruins the magnetic tape) when the drive motor turns the cartridge capstan.

A couple of things:

1) I've taken apart several cartridges and realized that, while time-consuming, it isn't that difficult to deal with the bands. Does anybody know if I can purchase replacement bands for these and just fix them all?

2) If I manually move the cartridge capstan very slowly, the band won't break and it will still advance the tape -- the necessary motion for reading the data. What are my chances for modifying the source code for tar, "st" (linux scsi tape driver), or some other piece of the software stack that grabs the data to slow down the scsi tape drive, either implicitly or explicitly, so that I can read the data without the tension bands breaking? I'm guessing that the torque created by the motor may well be outside of software control and that I can't, without electrical or mechanical intervention, keep it from tearing apart the rubber bands.

Thanks, Nate

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1. Have you tried contacting the manufacturers? 2. I highly doubt software can control the motor speed, it's almost certainly controlled by the drive's firmware. Something that old probably doesn't have flashable firmware either. – Chris S Jul 18 '10 at 14:39
Hi, Chris. Thanks for your reply. I do plan to contact 3M and ask them if they have tension bands. I was certainly hoping someone here might have a better solution, though. – user48641 Jul 18 '10 at 18:42
I think replacement bands is the best bet. I worked at a company that recorded EKG data to standard audio cassettes, to get 24 hours on a 60 minute tape, we ran the motors very slow. However to be able to keep the data readable, we had to back tension the 'supply reel', which would wear out the tape heads. Now our system wrote AND read at the slow speeds, I think you will have problems reading data that was written at another speed. BTW, I also worked in a plastics company that molded the covers, reels, and rollers for the DC300/600 3M tapes. Met my wife there... – BillN Jul 18 '10 at 21:14
Well, I contacted 3M, who referred me to Imation (the company that took over the DC600A division in 1996) and Imation said that because they discontinued the product several years ago, they closed the plant and hence have nothing left of the product. I guess if I find bands, they'll be makeshift/3rd party. The funny thing is, I only need a few good bands, as that would require not much more work than having 1 band/tape. Once I grab the data, I can just throw away the old tape. – user48641 Jul 19 '10 at 16:04
up vote 2 down vote accepted

It seems that your best source of tension bands may well be from other cartridges. If you can find some NOS (New-Old Stock) tapes in good condition, you may be able to "borrow" the bands from them so you can recover your data.

Not knowing what the bands look like, I'll hazard a suggestion anyway for replacements: If the bands are round in cross-section (not rectangular like a rubber band) try going to an auto parts store, and see if they have any O-ring seals which might fit. There is usually a huge assortment of them, and your chances of finding one which works well enough is pretty good. Even if the original bands were rectangular cross-section, an appropriately sized O-ring may work anyway -- at least for a while...

Best of luck, and please let me know if this helped!

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I'm giving Jesse the nod here just to close the question (at least conceptually close it). We bought newer tapes from ebay (the newest tapes with identical form factor but more storage) and tried to replace the bands on 2-3 tapes. Several of us vetted the work of our best band-replacer and each renewed tape looked fine, but we couldn't pull data off of the tapes. We were extremely careful in all parts of the process (believe me -- I spent WAY too much time digging into every possible aspect) and they didn't work. We don't have the time to deal with the tapes, so we had to give up. – user48641 Dec 6 '10 at 13:46
I want to thank everybody for their help. I expected to get 0 responses at the beginning. – user48641 Dec 6 '10 at 13:47

I know this sound like an Advertisement, but, did you try ebay? Some sellers are selling new tapes.

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Maybe this is a long shot, but maybe custom fabrication is an option.

I happened across this site today for 3D printers capable of outputting in metals.

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