Author Topic: 3M Magnetic Tape Viewer  (Read 1171 times)

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Offline Halcyon

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3M Magnetic Tape Viewer
« on: March 01, 2020, 08:25:27 am »


Easily the coolest thing I've seen for a while!
 
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Offline jonovid

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Re: 3M Magnetic Tape Viewer
« Reply #1 on: March 01, 2020, 01:29:17 pm »
interesting to know this is possible. 

maybe make your own? with some type of mechanical pinch roller raster scanning with a modified floppy or hard disk drive read-write head may just give you
a higher resolution magnetic tape viewer, maybe using an arduino, only time will tell. at $100 their is got to be a good reason to give it a try.

I do not have the reason to give it a go for now!
« Last Edit: March 01, 2020, 01:36:55 pm by jonovid »
Hobbyist with a basic knowledge of electronics
 

Offline mcovington

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Online RoadRunner

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Re: 3M Magnetic Tape Viewer
« Reply #3 on: March 02, 2020, 08:50:05 am »
I wonder why pattern appears to be a digital even though all tapes he tested are analog.  Does it only shows peaks at certain level.
 

Offline TimFox

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Re: 3M Magnetic Tape Viewer
« Reply #4 on: March 03, 2020, 03:38:00 am »
I wonder why pattern appears to be a digital even though all tapes he tested are analog.  Does it only shows peaks at certain level.
Magnetic tape is not linear.  Recording bias current swings the magnetic material from positive saturation to negative saturation at a supersonic frequency. The signal current shifts the ratio of positive to negative, giving a net magnetization that yields the audio signal after low-pass filtering in the playback head and amplifier.
 
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Online Berni

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Re: 3M Magnetic Tape Viewer
« Reply #5 on: March 03, 2020, 06:17:19 am »
I wonder why pattern appears to be a digital even though all tapes he tested are analog.  Does it only shows peaks at certain level.
My guess is that the particles get pulled together where the strongest field it so most want to concentrate on the peak, but i would also assume there is some minimum field strength required for anything to show up.

Quite a neat product, i could see this being very useful in the days of manually splicing together tapes.
 

Offline helius

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Re: 3M Magnetic Tape Viewer
« Reply #6 on: March 03, 2020, 08:05:41 am »
This product is related to magnetic "developer", a bottle of fine iron filings used to see data on magnetic tape.
If you had a reel of tape that was damaged somewhere in the middle, you could use the developer to see record boundaries and splice out the damaged record, which would enable most of the data on the tape to be saved. This was possible because reel tapes were longitudinally recorded in a single stream, with 9 tracks in parallel each representing a bit in a byte. There was a gap between each record where splices could be made without disrupting the data.
When tape decks started to switch to helical and then serpentine recording (approx. mid-1980s), it stopped being possible to splice tapes while preserving the data.
 

Offline bsudbrink

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Re: 3M Magnetic Tape Viewer
« Reply #7 on: March 03, 2020, 04:28:20 pm »
I wonder if it can "see" tracks on floppy disks.  8 inch, 5.25 or 3.5.
 

Offline ajb

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Re: 3M Magnetic Tape Viewer
« Reply #8 on: March 03, 2020, 05:01:19 pm »
I wonder if it can "see" tracks on floppy disks.  8 inch, 5.25 or 3.5.
That was addressed in the video description, and apparently the answer is no.  The pattern on floppies is too dense and/or too subtle to be visible with this gizmo.
 
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Offline cvanc

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Re: 3M Magnetic Tape Viewer
« Reply #9 on: March 03, 2020, 05:27:03 pm »
I vaguely remember these; didn't they have a membrane that had to be kept damp?
 


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