Techmoan shared this fascinating video on Youtube!

An intriguing piece of retro gadgetry that lets you view the magnetic patterns recorded on tape.

FAQs
Q) CAN IT SEE WHATS ON A FLOPPY DISK?
A) No – It didn’t show anything on a 5.25” floppy I tested (BOTH SIDES)
Considering the viewer is pretty much maxed-out for resolution by an 8 track, (8 tracks recorded on a tape 1/4” wide at 3.75 ips) I’d imagine that anything more dense than this will be beyond the capabilities of what can be displayed by the device. I’ll try an 8” disk soon – but I would be shocked if it shows anything for the same density reasons

Q) You can buy these sheets of magnetic viewing paper that do the same thing.
A) They don’t have the same resolution or sensitivity – at least the ones I’ve bought don’t. They can’t show the magnetic signal and track layout on a tape. Nothing registered when I tried.

Q) You can use this fluid stuff that does the same job
A) A few people are mentioning various ways to do this with a liquid smeared on the tape – These were known about – and likely made by 3M as well – but one reason for the development of the magnetic tape viewer was that it was a ‘non destructive’ way to read the tape – here’s an except form their patent application where they mention one of the existing and alternative methods to do the same thing.

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