Limiting CRT interference

obeseotron

Golden Member
Oct 9, 1999
1,910
0
0
Is there anyway to reduce the interference that is making the image on one of my 21" CRTs start to shake sometimes? Never happened until I moved to where I now live and it is very annoying. Turning on the microwave on the floor above me triggers the shaking effect every time, but sometimes it starts to happen even when the microwave is not running. I have another 21" CRT sitting right next to it that does not "shake" ever. This happens regardless of the refresh rate. Any ideas?
 

pkme2

Diamond Member
Sep 30, 2005
3,896
0
0
How about short waves, radio waves, or some magnetic interference of some sort.
A electric motor can have an effect too. Anything on same power line. High electrical powerlines, transformer of sorts.
Possibilities plus.........
 

Dethfrumbelo

Golden Member
Nov 16, 2004
1,499
0
0
I'm shocked that the little glass door on the microwave isn't stopping all that radiation from blasting out. I wonder how many people put their face right in front of the door as they watch something 'cook'.
 

butch84

Golden Member
Jan 26, 2001
1,202
0
76
I eventually gave up and went to lcds. I know that's probably not the answer you're looking for, but unless it's something obvious like fluorescent lighting, you might have a really tough time figuring out what's causing the shaking.
 

cparker

Senior member
Jun 14, 2000
526
0
71
I was having the same problem. Thought I had a broken crt. Then it would go away. Then it would start. Finally I noticed it was my 2.4 ghz roam phone. When it was on the same table as the crt it would cause it to get "the jitters". When I moved it away it calmed down.
 

vanvock

Senior member
Jan 1, 2005
959
0
0
I get that sometimes & I think it may be from the large trucking terminals that are being built near me since I never noticed it until they became operational & I guess they still use radios for some comm.
 

Jeff7

Lifer
Jan 4, 2001
41,596
19
81
Originally posted by: Dethfrumbelo
I'm shocked that the little glass door on the microwave isn't stopping all that radiation from blasting out. I wonder how many people put their face right in front of the door as they watch something 'cook'.

The mesh screen is what stops the microwave radiation. The holes are too small to let the microwaves through.

The "radiation" that is causing the CRT to shake is likely just the electromagnetic field from either the magnetron or the powerful transformer that supplies it. It seriously screws with wireless network signals too.
CRT's use finely tuned electromagnetic fields to get the electron streams to hit very tiny pixel targets at the front of the screen. Any outside influence can mess up this delicate alignment. Even Earth's magnetic field can cause problems. When I was repairing my monitor, turning it on its side turned this into this.
 

thegorx

Senior member
Dec 10, 2003
451
0
0
move it, I had the same problem, two monitors one shook very slightly and fast, barely noticable, big time headache, it was right next to a main power conduit
 

obeseotron

Golden Member
Oct 9, 1999
1,910
0
0
Sorry, I should have explained more. Cordless phones seem to be what causes the shaking when it's not the microwave. I don't have a lot of options in terms of eliminating it, but at least I know the screen itself isn't dying. Tried a different outlet and got less shaking from the microwave, but it's still there. Still don't know why one CRT (dell badged Sony) is so prone to this stuff while the NEC doesn't have any noticeable effect. I'm gonna see what happens if I move the desk to the other side of the room, but I don't have high hopes.

Someday I'll buy a 24" widescreen lcd and ditch the dual CRTs, but that won't be an option for a while.
 

IEC

Elite Member
Super Moderator
Jun 10, 2004
14,597
6,076
136
I remember when we would have fun with magnets/degaussing monitors in CompSci class in high school.... ah those were the days ;)

I had a 17" Sony Trinitron until it busted just out of warranty. It was a horrible PoS that made me vow to never buy a Sony product again (I'd had prior bad experiences). I went with a Samsung 15" LCD in 2001 for $350 :)o) and I'm still using it.

I most recently bought a 19" Widescreen Viewsonic LCD for $200, it's amazing how far LCDs have come in 5 years. Looks better than the CRTs I've used (with the exception of my cousin's massive 24" IBM :D)
 

KeithP

Diamond Member
Jun 15, 2000
5,664
202
106
Try a different outlet. The interference may be in the power, not in the air.

I have seen this problem a few times over the years and in all cases it was AC line noise on the electrical circuit causing the problem. I would try different outlets as suggested or get an electrician in to see what might be done.

-KeithP
 

Seekermeister

Golden Member
Oct 3, 2006
1,971
0
0
Originally posted by: KeithP
Try a different outlet. The interference may be in the power, not in the air.

I have seen this problem a few times over the years and in all cases it was AC line noise on the electrical circuit causing the problem. I would try different outlets as suggested or get an electrician in to see what might be done.

-KeithP
In my case, it was simply being plugged into the same circuit as the microwave...though in different rooms.