CRT Monitor Squiggling?

S

Synful Serenity

[H]ard|Gawd
Joined
Jun 4, 2004
Messages
1,256
My 2141SB from 2004 has recently started to act up....What happens is that at random times, random areas of the screen will shake very rapidly, what looks like squiggling. It usually lasts only a few seconds, and during that time the squiggling increases, and then dissipates. Sometimes I'll go for days without noticing this....other days it happens rather often. It's the totally random nature of this that has me puzzled though.....Seems to affect sections of a few inches radius at a time, and rarely more than half of the screen at once. Has anyone ever experienced something like this with their CRTs before?

I'm also curious if this could be power or interference related.....I do live in a condo building, if that helps. I really hope it's not the monitor....A good CRT is hard to come by these days!
 
It could be power, it could be interference, it could be physical, it could be electrical. We'd need a much clearer description of the problem in order to make a diagnosis as such a distance.
 
Ya that could be power related. I have a noisemaker about 3 feet from my monitor and when turned on it makes the left side of the monitor shake like that. It also happens when someone is using the vacuum in the house.
 
Possibly power related and also possibly how well the monitor itself is dealing with the power. I intermittently got this with my KDS 19" inch at 1280x960 @ 75hz. Had to back off to 72hz which cleared it up.

You can try backing off the refresh rate a little like I did, see if it helps.
 
I'll try to record the problem somehow....In the meantime, because of the sporadic, intemittent nature, the only further way I can describe it is this: Limit yourself to any 100 rows of pixels horizontally (so you'd be looking at a 1280 x 100 section, if your resolution was 1280 x 1024). Now suppose you look at the first row of pixels in this section and shift it 2 pixels to the right. Take the second row, and shift it 2 pixels to the LEFT. Continue alternating shifting the rows of pixels until you get to around 20 rows down. At this point, the rows will still appear to be shifting, but increase the magnitude to about 3 or 4 pixels...in the middle of the screen, the 10 rows of pixels in the center of the section should be alternating left and right up to about 10 pixels or so. For the remaining rows of pixels, they should be symmetrically shifting, but tapering down to mirror the top half (In reality, the shifts are more sporadic and uneven and not really that symmetrical, but it would look something like this, and it's easiest to describe. The area should now look something like this:
.--------------------------------------------------------------------------------------
... --------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------
....... ---------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------- .......
... ---------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------..

​

Have each of these rows now shift direction an equal number of pixels in the OPPOSITE direction about 10 times a second. Except after a couple seconds, increase the amount of distance each row moves by a few more pixels. In other words, the area of the screen is basically oscillating, and increase the strength of the oscillations. Then, reverse the process so the oscillations wind down during the last 2 or 3 seconds or so.

The net effect is that the screen is squiggling, like waves or someone "shaking up" the pixels, except when it happens, it varies in duration, intensity, and area of the screen involved.

I don't have any other electronic devices on or near the monitor. Is the behavior reminiscent of any specific cause you may be familiar with? Or rather, are there any common causes that may be ruled out by similar or dissimilar symptoms?

EDIT: Seems independent of resolution and refresh rate.
 
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