Degausing


I've just shifted my 80cm CRT from North-South facing to East-West, and
now have two faint but annoying colour blobs on the screen (small one
top right corner and big one middle left).
Turning the set on from cold the last few days has not made any difference.
Will an $80 degaussing wand from Jaycar fix this, or will it require an
expert to fiddle with the purity yoke magnets as well (in which case I
won't buy one)?
Reply to
Caliban
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difference.
Speakers nearby? Large magnetic fields? Nearby electronics?
Do the spots go away when you turn the TV back where it was? Do they move on the screen when you swivel it gradually back to where it was facing?
Coil of electrical wire inside the wall (assuming it's near a wall) generating a magnetic field? Some form of bolt or stud in nearby wall causing disturbance?
Reply to
Mark H
Only the centre speaker but it is well shielded (B&W303) and in the same place it was before. Moving the centre speaker makes no difference.
It weighs a tone - I'm not shifting it again in a hurry - and I can't really swivel it in the (wooden) entertainment unit, but Ill give it a try.
Unfortunately I doubt it, it's backed against a (nearly full wall) window with all wood construction and wooden Venetian blind.
Reply to
Caliban
Judging from the odd tv manual i've read (haha) leaving the set unplugged in its new location for so much as half an hour might set this right.
Reply to
Nathan L,
Hi Caliban,
While assembling some 3-way loudspeaker enclosures I made the mistake of leaning a front panel, complete with speakers, against the front of my 68cm CRT TV. The result was a large more or less permanent blob of colour right in the middle of the screen.
Presumable I'd made a good job of magnetizing the shadow mask.
My solution:
Take a 2 mH aircore inductor from the Bass-Midrange cross-over and connect it to the secondary of a Scope soldering iron transformer (Can anyone remember them?) via 1m of speaker cable. The ~4V resulted in about 6.5A which the coil could take more or less permanently without overheating.
Sweeping the coil back and forward across the screen a few times did the degausing for me.
Cheers,
Don Keogh Donald B Keogh
Reply to
Donald B Keogh
I recently had a science class full of year 3's. I handed out the bar magnets and in less than 30 seconds one of the littil darlin's had crossed the room and slammed his magnet against the computer monitor like he knew damn well what it would do. I was livid!! Thank God it had a degauss circuit, so it survived unscathed.
Reply to
Tim Polmear
"Tim Polmear"
** Clearly the young person concerned appreciated the likely effect of a magnetic field on the path of an electron travelling at 1/2 the speed of light and was keen to give all present a simple demonstration ;-)
** I would have asked him/her to explain the visible results to the class and then marked their answer out of 100.
** TVs would hardly be kid safe otherwise.
............ Phil
Reply to
Phil Allison
Thanks for the info.
I'm going away for a couple of weeks but will give this a go when I get back. Jaycar seem to be out of stock of the degaussing wands. I have an old Weller soldering iron transformer (24V I think), and will build something similar.
Just one thing, I thought you were supposed to wave the wand in slowly increasing circles as you move away from the TV.
Reply to
Caliban
Could an old TV degauss coil be used with low voltage ?
Gordon
Reply to
Gordon W

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