1 Jun
2004
1 Jun
'04
3:49 a.m.
Try a piece of sheet steel between the monitors..
You're probably
suffering from stray magnetic fields.
Any particular kind of steel? Will the metal from Air conditioning ducts
work? (I can get flat peices of that cheap at the local Home Depot).
-chris
<http://www.mythtech.net>
4:15 a.m.
On Tue, 1 Jun 2004, Ed Kelleher wrote:
At 11:49 AM 6/1/2004, you wrote:
Please don't do that unless you want a semi-permanent distortion field in
the middle of your screen.
--
Sellam Ismail Vintage Computer Festival
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Any particular kind of steel?
The kind magnets will stick to.
Hold the magnet on the screen of a CRT to see similar distortion. 
4:41 a.m.
On Tue, 1 Jun 2004, Ed Kelleher wrote:
The kind magnets will stick to.
Hold the magnet on the screen of a CRT to see similar distortion.
Are you volunteering to have the monitor repaired after he does that???
Many times such a course of action will magnetize the shadow mask and
other parts of the CRT beyond the ability of the internal degaussing coils
to correct.
But O well.....
To the original poster:
As for stacking tubes one on top of the other - if it's just the one
that's causing the magnetic pollution, I'd be inclined to chuck it (at
your appropriate nearby E-Cycling facility of course!) and just get
another. They're common as dirt and as folks trade up to LCD screens, CRT
monitors are hitting the recycle streams in epidemic quantities. Nobody
wants a 100-pound 23" CRT that takes up half the desk anymore...
If you must shield them, then use reasonably thick (1/8" to maybe 3/16")
*iron* sheets if you can it - magnetic steel if you can't.
And Home Depot. Lowe's, etc are going to stick it to you if you buy such
materials there... it's unbelievably outrageous what the charge for bar
stock, angles, and sheets.... any little funk metal shop or machine shop
will have tons of this stuff lying around for cheap...
Just my 200 millidollar.
John
6:40 a.m.
On Tue, 1 Jun 2004, John Lawson wrote:
And Home Depot. Lowe's, etc are going to stick
it to you if you buy such
materials there... it's unbelievably outrageous what the charge for bar
stock, angles, and sheets.... any little funk metal shop or machine shop
will have tons of this stuff lying around for cheap...
I can certainly attest to that. An 8 foot length of 1 1/4" angle
aluminum costs $15.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
10:23 a.m.
On Tue, Jun 01, 2004 at 11:40:45AM -0700, Vintage Computer Festival wrote:
On Tue, 1 Jun 2004, John Lawson wrote:
Speaking of which... does anyone know where I could order a few lengths
of 2" wide x 1/2" or 3/8" thick aluminum bar? It would have to be
someplace
that could send it either directly to me to me via the Post Office; or to my
boss in Madison, WI, via whatever means, so that he could bring it to me
when he arrives in October.
It's for a frame for my SBC-6120 - I would need two pieces approx 16" long
and two pieces approx 10" long to make the box.
-ethan
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And Home Depot. Lowe's, etc are going to
stick it to you if you buy such
materials there... it's unbelievably outrageous what the charge for bar
I can certainly attest to that. An 8 foot length of 1 1/4" angle
aluminum costs $15. 
10:48 a.m.
Ethan Dicks wrote:
On Tue, Jun 01, 2004 at 11:40:45AM -0700, Vintage
Computer Festival wrote:
Have you checked out small parts, thay have some interesting hardware.
http://www.smallparts.com/
On Tue, 1 Jun 2004, John Lawson wrote:
Speaking of which... does anyone know where I could order a few lengths
of 2" wide x 1/2" or 3/8" thick aluminum bar? It would have to be
someplace
that could send it either directly to me to me via the Post Office; or to my
boss in Madison, WI, via whatever means, so that he could bring it to me
when he arrives in October.
It's for a frame for my SBC-6120 - I would need two pieces approx 16" long
and two pieces approx 10" long to make the box.
-ethan And Home Depot. Lowe's, etc are going to
stick it to you if you buy such
materials there... it's unbelievably outrageous what the charge for bar
I can certainly attest to that. An 8 foot length of 1 1/4" angle
aluminum costs $15. 
4:09 a.m.
>>>> "chris" == chris
<cb(a)mythtech.net> writes:
> Try a piece of sheet steel between the monitors..
You're probably
> suffering from stray magnetic fields.
chris> Any particular kind of steel? Will the metal from Air
chris> conditioning ducts work? (I can get flat peices of that cheap
chris> at the local Home Depot).
I'd say "anything that magnets stick to" (which means most kinds other
than certain stainless alloys).
Purists would use mu-metal; if the plain steel works, mu-metal would
work better. But it's probably hard to find.
paul
4:31 a.m.
At 12:09 PM 6/1/2004, you wrote:
Purists would use mu-metal; if the plain steel works,
mu-metal would
work better. But it's probably hard to find.
Plus MuMetal is sensitive to mechanical working.
Beating a piece to straighten it out will reduce it's effectiveness.
Galvanized sheet steel used in AC ducting should be fine.
As would a skin from a computer chassis.
Layering might help.
Also, the sheet might need to extend past the sides, and front and back of
the monitor to intercept lines of flux from source.
I wonder if degaussing the target monitor (one with interference),
while the source monitor (creating the interference) was operating, would help?
Some monitors have a built in degaussing function.
Others do it when they power up.
The above all assumes a magnetic interference.
If it's localized to one, or a few, spots on the screen, with color shifts,
that's likely what it is.
Of course that gets me to thinking of TEMPEST and someone reading your
monitor from out in the street. :-)
Ed
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