Substituting DSHD for DSDD disks (or DS2D if you prefer)

Eric Christopherson echristopherson at
Sun Oct 25 15:05:39 CDT 2015

On Sun, Oct 25, 2015, Joseph Lang wrote:
> This list seems to me to be populated with "build your own" types, so make your own degausser. 
> Decades ago I repaired the tape eraser at the TV station I worked at. Once I saw how it was built I built my own. Take a transformer (something about 100 watt or more) pull the laminations out (the hard part) line up all the 'E's put them back. Discard the 'I's. 
> It will buzz like mad and get hot in a minute but produce a very strong AC magnetic field. 
> Keep it away from your shadow mask color TV!
> Joe
> > On Oct 25, 2015, at 1:01 AM, Chuck Guzis <cclist at> wrote:
> > 
> > On 10/24/2015 09:06 PM, Eric Christopherson wrote:
> > 
> > 
> >> Fascinating -- I didn't know there were AC and DC magnetic fields.
> >> How strong is "very strong", and would the library device I mentioned
> >> count toward "an AC erase"? Should I assume that just doing an AC
> >> erase would be insufficient?

I guess my last question (would doing just an AC erase, by whatever
means, always be insufficient) got lost.

> > 
> > The AC unit I use is a VHS tape bulk eraser.  It's pretty strong and has a limited working time--maybe 2-3 minutes before the thermal cutout interrupts.  Let it cool for a few minutes and get back to work.
> > 
> > How strong a DC erase?  I suppose that one of these magnets could well lift a 100 lbs.  Scary strong.
> > 
> > --Chuck
> > 

        Eric Christopherson

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