On Fri, 22 Apr 2005 23:55:41 +0200, Norbert Hahn
wrote:

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http://www.radiomuseum.org/dsp_forum...thread_id=6955

HTH
Norbert

Cute! -- This is a translation of instructions for demagnetizing a
head of, I presume, a Normende tape recorder. It must be a quite old
gear, tube maybe. This is a somewhat risky procedure as it involves
mains voltage area so don't try it at home (blah but I had to tell
it). I translated it as close to the German original so the
translation is not "styled":


Demagnetizing a Reproduce/Record Head.

It is important for an accurate functioning of a tape recorder that
the reproduce/record head has no remanent magnetism whatsoever. An
unwanted magnetisation appears by the use of magnetized tools or by
lack of a due care during repairworks. The remanent magnetism in a
head is recognized by an uneven noise at the reproduction of an erased
band.

Demagnetization of a head can be carried out as follows. A paper
condenser, approx. 0.25 uF / 250 V DC, charged by a DC source (eg. at
the mains filter electrolytic capacitors of the tape recorder) is
shortly connected in parallel to contacts 1 and 4 of the monitor
socket (V 302). This procedure is to be repeated several times, for
the track 1-4 as well as the track 3 - 2.*


* I think they meant the two head pins for each of the stereo tracks.

Edi Zubovic, Crikvenica, Croatia