Magnetized Tape Heads

[mcp6453]

Is there a simple way to tell if the heads on my Nakamichi Dragon cassette
player are magnetized OTHER than listening for the high frequency loss? The
manual says to demagnetize the heads every 50 hours. Demagnetizing heads scares
me, even though I have a professional demagnetizer, if I can find it.

[Don Pearce]

Nothing scary about demagnetizing. Just bring the tool up close - but
not touching, then power it up and move it way as slowly as possible.
It is most important to move really slowly at the start - magnetism
decreases as the cube of distance, not the square, so the effective
field doesn't extend as far as you may think.

d

[Scott Dorsey]

Annis will sell you a magnetometer so that you can tell if there is a problem,
then they'll sell you a demagnetizer so you can fix it if you have a problem.

Head magnetization problems are so rare today that I would not even bother.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[William Sommerwerck]

I have, on occasion, demagnetized tape heads, and never caused any harm.

If you're nervous, practice with the demagnetizer turned off, for slow, smooth
movement.

[Sylvain Robitaille]

What is this "magnetization" and "cassette player" that you speak of???
;-)

I have a bit of heat-shrink tubing shrunk around the business end
of my demagnetizer (done so long ago it feels like it's always been
there!), to protect against accidental contact. I don't recall that
it ever had to be invoked, though. That said, I can't remember how
long it's been since I used the demagnetizer (or any cassette deck
for that matter ...)

Still, I hope you find the idea helpful.

--
----------------------------------------------------------------------
Sylvain Robitaille s...@encs.concordia.ca

Systems analyst / AITS Concordia University
Faculty of Engineering and Computer Science Montreal, Quebec, Canada
----------------------------------------------------------------------

[Tobiah]

Just an aside, I had a friend long ago who's car had an 8-track tape
player in it. She bought a head demagnetizer for it. It was an 8-track
shell, with a lever on the external end that caused a magnet near the head
to move back and forth when you moved the lever. The instructions were to
keep the magnet moving back and forth at a constant rate while pulling the
whole cartridge out as slowly as possible. Not sure whether it did more
harm or good.

Tobiah

[Trevor]

"Tobiah" <to...@tobiah.org> wrote in message
news:GA7nu.395566$jg4.1...@fx05.iad...

> Just an aside, I had a friend long ago who's car had an 8-track tape
> player in it. She bought a head demagnetizer for it. It was an 8-track
> shell, with a lever on the external end that caused a magnet near the head
> to move back and forth when you moved the lever. The instructions were to
> keep the magnet moving back and forth at a constant rate while pulling the
> whole cartridge out as slowly as possible. Not sure whether it did more
> harm or good.

Permanent magnet "demagnetisers" almost always did more harm, if they did
anything at all.
Then there were the pulse type cassette shell demagnetisers that also relied
on the fact users had no way of checking they didn't help, but usually
caused less harm than the permanent magnet types at least.

Trevor.

[Scott Dorsey]

In article <GA7nu.395566$jg4.1...@fx05.iad>, Tobiah <to...@tobiah.org> wrote:
>
>Just an aside, I had a friend long ago who's car had an 8-track tape
>player in it. She bought a head demagnetizer for it. It was an 8-track
>shell, with a lever on the external end that caused a magnet near the head
>to move back and forth when you moved the lever. The instructions were to
>keep the magnet moving back and forth at a constant rate while pulling the
>whole cartridge out as slowly as possible. Not sure whether it did more
>harm or good.

These things, like similar ones for cassettes, are far more apt to do
harm than good.