Degauss and hard drive

[Avinitlarge]

I have a small concern. Will the degaussing coil affect the hard drive?

[endrien]

Only if its very close to a hardrive. I've ran a decently powerful magnet over the top of my laptop and it did nothing.

[DJ_Izumi]

A PC CRT monitor often sits no more than a foot or two from the case that houses the HDD.  The degause doesn't damage that.  Of course the HDD is inside the case which acts as a faraday cage.  I wouldn't risk putting the HDD barebones directly adjactent to the monitor or something.  But if it's in the case and there's a bit of distance, I wouldn't be worrying.

[mvsfan]

The magnetic field is about 8 inches to a foot out from the monitor, thats all. You can find out easily where the field stretches to by taking a speaker magnet and moving it closer and closer to your monitor until you see a slight color change adjacent to the magnet. when you find that, that is the beginning of the magnetic field of the monitor.

basically, you want your harddrive outside of that.

and if you have any doubts like a Dynamo with the pull out pcb shelf, always remember that any steel plate acts as a RF sheild.

basically, if your uncomfortable after the test, go find a thin steel plate big enough to mount between the monitor and the bottom of the cabinet and you will be set.

[mvsfan]

one thing to note though is dont tempt fate and keep moving the magnet closer even though you see the change cause at best youll have to degauss it at worst you can do damage to it.

[DJ_Izumi]

The magnetic field is about 8 inches to a foot out from the monitor, thats all. You can find out easily where the field stretches to by taking a speaker magnet and moving it closer and closer to your monitor until you see a slight color change adjacent to the magnet.

Uhh, the CRT monitor doesn't put out any signifigant magnitism.  That's why nothing metalic sticks to your monitor.  All you're seeing there is how close the magnet has to be to screw with the monitor.  That's nothing about the magnetic field of the monitor but of your speaker magnet.  Also, he's talking about the degause coil, which fires off on power up and on command if the shadow mask gets magnetized.  That's a frequent but one of event, not a peristant field.

[Avinitlarge]

Also, he's talking about the degause coil, which fires off on power up and on command if the shadow mask gets magnetized.  That's a frequent but one of event, not a peristant field.

Thats right, It only fires once when the screen is powered up, That only depends on the temp of the positor too. If the positor is warm, It bearly fires if at all

[mvsfan]

The magnetic field is about 8 inches to a foot out from the monitor, thats all. You can find out easily where the field stretches to by taking a speaker magnet and moving it closer and closer to your monitor until you see a slight color change adjacent to the magnet.

Uhh, the CRT monitor doesn't put out any signifigant magnitism.  That's why nothing metalic sticks to your monitor.  All you're seeing there is how close the magnet has to be to screw with the monitor.  That's nothing about the magnetic field of the monitor but of your speaker magnet.  Also, he's talking about the degause coil, which fires off on power up and on command if the shadow mask gets magnetized.  That's a frequent but one of event, not a peristant field.

you answered your own self here dude.

IF the Shadow mask Gets Magnetized.

Basically if you bring your magnet too close for too long you either have to wait a long while or call it up to manually degauss again or run a self serving deguass coil to restore the colors.

No the shadow mask isnt persistant field, but just try and keep it externally magnetizied for a good length of time.

what ive said still stands.

[mvsfan]

you need to demonstrate for a fact and prove me wrong point for point to win this outright.

[mvsfan]

any experience that ive had with crt monitors since the beginning of time says that their should never be less than 6 inches between one and a hard drive without a solid steel plate no matter how thin up to 1/16th inch thin, without having or experiencing significant data loss over time.

[mvsfan]

The main and only reason most people just dont worry about it is cause almost all store bought as well as homebuilt PCs have a metal case thus its not an issue.

it only becomes an issue when someone is building an uncased pc thats destined to reside inside of a mame cabinet.

if you want to just stick a pc case and all in your cabinet its not an issue at all.

if your one of the people like me who feels that it lends a great deal of authenticy to open a cabinet to show someone and they see nothing but circuit boards, the botom line is that that is where and when monitor interference does become an issue.

[DJ_Izumi]

Wow, spam much?

[telengard]

I've had no issues w/ degaussing and I do it a lot (rotating monitor).

Now my speakers making noise when copying files over the wireless network adapter, that's another story...

~telengard

[Beretta]

like mvs said a steal plate will dampin the magnetic field considerably.. so inside the typical pc case it's pretty well protected.

the hdd's housing it self is usually aluminum.

i'd say if you got a foot or so distance it should'nt be a issue.. but if you wanna be on teh safe side either put a plate between the monitor and the hdd or use a case in teh cabinet.

in a upright i dont think it's a issue.. in a cocktial i'd just put a plate or build a cage out of sheet metal for the hdd..

you could also look at things like soldstate or flash drives, or self booting cd/dvd instead of using magnetic hdd.

i have a server cobbled out of spare junk parts using BTX form factor.. not having a case i mounted it on a piece of scrap wood..

a 21 inch crt monitor sits about 2 feet away, also roughly 18 inches above it is also a large box fan in a open window..

it's been operating this way for roughly 5 years on the same OS install, no corruption yet.

they are more resilient then you might expect and unless it's making love to the monitor i dont think it will be a issue.

[DJ_Izumi]

Same thing, I have a pair of P1110's sitting 3 inches away from my tower that has the case sides removed.  These things are strong enough that when one powers on from cold, it'll degause the one next to it in the process.

But heck, most PCs have a PC speaker INSIDE the case which presents more of a magnetic field at closer range to your PC guts than a monitor ever will.

[protokatie]

Fun experiment for you kiddies: Put a 3.5 floppy on top of your monitor and hit the degause button 50 to 100 times... Guess what. The disk will be fine. Just dont be MOVING the disk WHILE you are hitting the degause button, that will ---fudgesicle--- it up (magnetic flux).

BTW Aluminum is a good electrical conductor as well as a good EM inductor, so it should work well as a faraday cage. If you are REALLY worried about data loss, get an old steel food can (one big enough to put the drive in) and use that. Hell, even better, shield the monitor, and any potential interference to anything (not just HDDs) will be eliminated.

No offense, but people worry way to much about a very small amount of EM way too often. But I guess it is better to be safe than sorry. (Also, used steel food cans cost nothing, but you have to actually BUY sheet metal...)

EDIT: No matter what you decide: A faraday cage has to be grounded to work properly. The point of it is to absorb EM and convert it into electricity. If grounded it can "vent" the electricity (doesn't really work quite like that, but the cage needs to be grounded to work fully).

[Avinitlarge]

Well, I wasnt expenting so many replies. So to be on the safe side, I will put the HD in a aluminium case and ground it. It will be moumted about 60cm away from the tube.

[Beretta]

thats a really good tip protokatie, infact i would never have thought of using old cans for their metal, but i might just make me some brackets out of them, was gonna use old sheet metal from dead cdroms and slot covers but food cans would be a easy source, why did'nt i think of that. 

Avinitlarge there is no reason to put them in an aluminum cage, 99% of the drives out there have their housings made out of aluminum already.

i did'nt know aluminum inhibited magnetic fields, but if thats the case then you should be fine, the housing on the hdd should be grounded already through the power connector, if you're extra worried run a jumper cable from the power supply's housing to the hdd's housing.. theyed be electrically connected in a metal case anyway, and the powersupplies housing is grounded.