How to use the magnetizer demagnetizer?

How to use the magnetizer demagnetizer?

Magnetizer Demagnetizer tool VTMD belongs on every work bench. It will magnetize and demagnetize the tips of screwdrivers and many other kinds of steel tools. It takes only seconds to magnetize or demagnetize your tool.

To magnetize, just insert the tool tip in the magnetizer hole and gently but rapidly shake the tool from side to side in the hole for a few seconds. Repeat if necessary to achieve magnetism. To demagnetize the same tool, repeat the procedure in the demagnetizer hole.

There are two concerns when using a demagnetizer:

First, is the field from the demagnetizer strong enough to demagnetize the heads and guides? And second, when is it far enough away so that you can shut it off without remagnetizing the heads and guides?

Demagnetizing:

If the demagnetizer is to demagnetize the core laminations, then the field that it produces must be large enough to cause the induction (flux density) in the core to approach saturation. When saturation approaches, the head output voltage waveform becomes distorted. But by this time the output voltage level is about 50 dB greater than the maximum output from tape, and the playback head preamplifier will surely be completely overloaded. Thus to perform this test you must disconnect the head and connect it directly to an oscilloscope input, and look for distortion in the waveform.