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View Full Version : Degaussing units, can they be used in our hobby



aboard_epsilon
06-17-2010, 09:22 AM
From time to time in car boot sales i see these round pancake Degaussing things ..used for Degaussing CRT tv sets....often very cheap.

my question is

1. can these be used to de-magnetise tools

2. can they be used to wipe hard-drives.........as i have a seagate 500GB hard drive thats failed at less than two years old with only 16,000 hours on it, im told the the warratie is is 3 years ...but dont want to give to to them with all my passwords ...and cracked progs on ..

all the best.markj

Tony Ennis
06-17-2010, 10:15 AM
Evan has a degausser. I bet he makes an appearance soon.

RKW
06-17-2010, 10:52 AM
Degaussing coils are for removing charges ... so yes. But maybe if the coil is so large it will not work as well on concentrated areas as a smaller one? I guess you could try it and see.

Any coil that is powered by AC rather than DC could be used for such ... some better/stronger than others like the commercial units with massive transformers.

I use a couple of AC solenoid coils that work great that I have cheater cord attached to. Small tools fit right through the hole in the coil.

Evan
06-17-2010, 11:50 AM
Making a demagnetizer is as easy as pie. Find any power transformer that takes regular mains voltage as input and either remove the top lamination block as found on really cheap transformers or cut off the top taking care not to cut the windings. Cut back the secondary wires and tape them over so that none of them are connected to anything. Hook up a powercord and insulate. The larger the transformer the bigger the items it can demagnetize.

All done. Do not run it for more than about 10 seconds at a time every minute or two. It will quickly overheat if you do. To demagnetize something turn on the unit and bring the item close to the core and then draw it away before shutting off the power. A foot switch is ideal for this. I have one that also serves as an extension cord.

http://ixian.ca/pics7/degauss.jpg

Evan
06-17-2010, 11:56 AM
can they be used to wipe hard-drives.........as i have a seagate 500GB hard drive thats failed at less than two years old with only 16,000 hours on it, im told the the warratie is is 3 years ...but dont want to give to to them with all my passwords ...and cracked progs on ..


If you degauss a hard drive you will destroy it permanently and they won't honour the warranty. Modern hard drives use prerecorded servo tracks on the platters that are created by a servo track writer before they are assembled. The servo tracks are used to locate the read/write heads during use. They cannot be rewritten by the drive itself as it has no other reference to head position. That is why it isn't possible to do a true low level format on modern drives.

aboard_epsilon
06-17-2010, 01:57 PM
well i cant format it ..cause its faulty.

will try and format it with the floppy..boot-it prog

all the best.markj

JoeBean
06-17-2010, 08:25 PM
well i cant format it ..cause its faulty.

will try and format it with the floppy..boot-it prog

all the best.markj

I don't think you need to go to these lengths to blank the drive. Seagate et. al. have pretty strong policies on handling RMA'd equipment. Your dead drive will be destroyed and recycled. In particular Seagate's policy is apparently to disassemble, test & reuse some components, but to degauss, drill and recycle the platters.

Assuming that the drive has mechanical problems (ie. crashed) nothing save very expensive equipment is going to get info off the drive anyway. So it's not like Jim Stealsalot from 3rd shift is going to be able to pocket your drive, bring it home and pull off your cc #'s.

If it hasn't crashed it's possible the problem is with the electronics on the board. You could get a replacement board from eBay and give it a try. It will void the warranty but for a couple bucks may revive the drive.

As for the issue with degaussers voiding the warranty, even though everything Evan said is true, from a practical standpoint I don't think that degaussing will present a problem, at least not with Western Digital or Seagate. I've returned a number of their drives that we've ran through a commercial HDD deguasser and I've never had a problem. Some degausser companies actually suggest using their devices before warranty returns, so I'm assuming this is pretty much typical. Realize, though, that without having the proper degausser that's been properly designed and tested you're not really going to be able to be sure that the drive you've "destroyed" really has no data. Even with a commercial unit you're basically going to have to take the word of the company selling it. HDDs are tough and they're resistant to magnetic corruption.

jugs
06-18-2010, 07:58 PM
I use a Degaussing unit on -

All stuff that's been on the magnetic chuck on the surface grinder (to remove all grinding crap),

Milling cutters / drills etc (so swarf clears away ).

Any steel I want clean.

Conversely

I also sometimes magnetize screwdrivers & small spanners to help get screws / nuts into difficult places

Hope that helps
john
:)

Duffy
06-18-2010, 08:08 PM
If you just want to demagnetize screwdrivers, tool bits and other slender stuff, use a shaded pole motor. Get one from a bathroom fan, for example, and remove all the rotating bits and bearing supports, (usually two bolts.) Wire the leads through a cord with a momentary switch. Press switch on, pass object into and back out of the hole in the laminations and let switch off. Best to remember Evan's 10-second rule.

reggie_obe
06-18-2010, 09:01 PM
Good for stopping your pacemaker as well.

lost_cause
06-18-2010, 10:22 PM
you can download a "low level format" utility from the manufacturer of your drive. this utility will write zeros to the drive, essentially erasing all data. it should return the drive to the same state it was in when purchased,

at least you always have been able to get and use these programs. i assume that new drives still work with these utilities.

Evan
06-18-2010, 10:35 PM
Writing zeros isn't a low level format regardless of what they call it. The early drives used stepper motors to position the head to each track and since that position was independent of the actual platter it could be repeated at any later time. This allowed the drive to regenerate all block headers and other tracking data as well as making it possible to set the heads off the center of the track to erase the edges of the data in the guard bands.

That isn't possible with a voice coil drive so the most that can be done is to write zeros to the existing tracks. If anything happens to the actual format data and the servo tracks it cannot be recreated whereas with the old stepper head drives it could be.

Rich Carlstedt
06-18-2010, 10:58 PM
For screwdrivers and slender items, just pass it through
a soldering gun inside of the loop that heats the tip..
Never, ever stop power on any demagnitizer until the workpiece is clear of the field, or else you might just remagnitize it again

Rich