Microdrives- has anyone managed to replace the tape ?

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Re: Microdrives- has anyone managed to replace the tape ?

Postby midboss » Sun Feb 26, 2012 12:26 pm

That bloke in the first vid could be Yuen Biao. Very athletic moves!


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Re: Microdrives- has anyone managed to replace the tape ?

Postby tcat » Tue Jul 02, 2019 1:45 pm

Hi Brane,

I had a simple scheme in mind:

- cut the original loop at head position.
- glue new tape to the end that comes from the outer end of the tape ring in the cartridge.
- pull the other end and let the glued end suck-in my new tape
- keep pulling until I pull all original tape out
- recut both ends so that they match and glue them together.

Trying to revive an old topic, I've had this in my mind, too. Any luck cutting the VHS tape?

I have sent a couple of enquiries to film making lab studios here, they are very good in cutting films across. My question was, if they could also cut a film (VHS, MiniDV), alongside.

Guess, no reply. I also went to a nearby university lab, they have a single beam laser machine. We tried to make an experimental cut, adjusting the beam power accordingly for the VHS material. Even then, the cut was not perfetcly regular.

S-O-S, any luck, ideas out there?
Tomas


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Re: Microdrives- has anyone managed to replace the tape ?

Postby pjw » Tue Jul 02, 2019 2:41 pm

tcat wrote:S-O-S, any luck, ideas out there?
A vice, a rubber eraser, a razor blade or surgical knife. Cut the eraser into two pieces of the required thickness, jam the razor blade between the two pieces of rubber in the vice. The gap between the vice jaws must be the width of the tape to be cut. Gently draw the tape across the blade. Voila!


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Re: Microdrives- has anyone managed to replace the tape ?

Postby tcat » Tue Jul 02, 2019 4:25 pm

Hi Per,

Good idea. I was also thinking to put as many razors 1,9mm appart, as fit across VHS tape width, but then it would reuquire a lot more force to pull tape through the blades.

Also, it may need a very good tape guiding from either side. Possibly, the vice can be mounted by screws right on the plastic VHS tape case. And with a bit of luck and some further adjustments, cut right inside a video recorder?

Still not sure is easilly DIY manageable.

Tomas


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Re: Microdrives- has anyone managed to replace the tape ?

Postby Dave » Tue Jul 02, 2019 7:36 pm

I saw this process at a factory in Basildon in the early 90s. I was buying bulk custom wound to length tapes, and they were buying their tape on huge 20cm*20,000 metre rolls. (or something like that. It was a long time ago.) I went there to pick up 5,000 wound to length tapes.

The cutters are circular. They are angled very slightly apart to form a semi-circle. I believe this is so the angle of the edge is parallel between blades to not damage the tape edge. The tape is drawn across the circular cutters at about a 30 degree angle. A roller before and after the cutters holds the tape down so it can't push up over the rollers. The cut tape then plays out in a similar ark to the cutters onto individual rolls that are all turning together, driven by compressed air.

From what I recall, they said they used circular blades because the tape was very aggressive and blunted sharp edges quickly. A piece of tape run over a static blade, it will blunt in a few thousand feet. A circular blade would go for a couple of million feet.

Does anyone know the formulation and bias EQ of microdrive tape? I understand it was just dry lubricated video tape.


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Re: Microdrives- has anyone managed to replace the tape ?

Postby pjw » Tue Jul 02, 2019 10:28 pm

tcat wrote:Good idea. I was also thinking to put as many razors 1,9mm appart, as fit across VHS tape width, but then it would reuquire a lot more force to pull tape through the blades.
Just remember to change the blades every few thousand feet ;)


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Re: Microdrives- has anyone managed to replace the tape ?

Postby bwinkel67 » Wed Jan 22, 2020 6:43 am

So microcassettes are 3.81 mm wide (same as standard compact cassettes) and microdrives are around 1/16 of an inch which is about 1.6 mm wide. So watching Techmoan the other day I saw this:

https://www.youtube.com/watch?v=t5FqjQlFBDM

Picocassettes are thinner than microcassettes. I haven't found a spec for them yet online but at 1:45 in the video you can see that it's about half the size of a microcassette (at 3.81 mm). So that comes to 1.9 mm for the picocassette. The "half size" is just eyeballing it so it may be close to or exactly 1.6 mm. Quality of tape I don't know and the picocassetts are also hard to come by, though one seller on eBay has more than 10 at $8.95/each currently (which includes shipping). One tape holds 30 minutes per side and the tape speed is 9 mm/sec which comes out to be 16,200 mm of tape length which is 53 feet of tape. I took a microdrive apart recently because the tape broke and I lost one end of it but don't recall how many feet it is though it wasn't close to that.

At 7.25 he talks about the Sony NT which is a higher quality digital tape but it is thicker at 2.5 mm (there is a spec for it). Even though it looks the same size you can see that its a tiny bit thicker in the case (or the picocassette maybe had more blank area in its width).

So, an analog cassette, would that work? I know the microdrives used a quality of tape similar to video recording tapes but it would be an inexpensive thing to try and spool one of these at the right length onto a microdrive and see what you got. I think Mattel used to have a video recorder that recorded on compact cassette which didn't work well but could still capture grainy black and wide video and sound so maybe the quality of the tape could work. Still, at $8.95 it might be worth a try as I do have an open cassette with the tape pulled out (and spooled on a paper roll presently).


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Re: Microdrives- has anyone managed to replace the tape ?

Postby Chr$ » Wed Jan 22, 2020 9:41 am

I've actually got some original cartridges that were written to once, then never sold and have been sitting around all this time. Once I've replaced the felt piece they seem pretty damn reliable.


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Re: Microdrives- has anyone managed to replace the tape ?

Postby tofro » Wed Jan 22, 2020 10:05 am

Chr$ wrote:I've actually got some original cartridges that were written to once, then never sold and have been sitting around all this time. Once I've replaced the felt piece they seem pretty damn reliable.


The problem with the cartridges actually seems to be not so much the tape, but rather the felts. If you don't mechanically destroy the tape and the felt is OK (thus, not causing the former), the tape can last virtually forever (expressed in relative terms ;) ).

Tobias


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Re: Microdrives- has anyone managed to replace the tape ?

Postby Chr$ » Wed Jan 22, 2020 10:15 am

tofro wrote:
Chr$ wrote:I've actually got some original cartridges that were written to once, then never sold and have been sitting around all this time. Once I've replaced the felt piece they seem pretty damn reliable.


The problem with the cartridges actually seems to be not so much the tape, but rather the felts. If you don't mechanically destroy the tape and the felt is OK (thus, not causing the former), the tape can last virtually forever (expressed in relative terms ;) ).

Tobias

Yes, when you have a 'good' one, i.e. one that was looked after and where the felt was replaced before it could do any damage, they seem to be generally ok. I do find some used ones that don't behave though and I think if they have seen a huge amount of use they are less likely to be reliable.


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