Weird screen wobble?

[Elheru Aran]

Hello,

I have a fairly current (~1yo) HP Pavilion PC with a ~10-yr old Dell CRT monitor.

Lately I've noticed this curious effect on the CRT, where the picture starts wavering or 'noodling' vertically.

Interestingly enough, there seems to be a correspondence with this fluctation and whenever my cell receives a text or call, as I tend to keep my cell on the desk by the monitor; my reception is utter shite inside the house, and the best place for it to consistently receive messages is up by the window.

Of course, the CRT could just be giving out, but it's definitely noodling anytime the text flashes up.

So what's up with that?

[Elheru Aran]

Ghetto edit:

Confirmed. Just wavered when I got a text in a couple minutes ago, and same thing happened when I replied. Weird.

[TheFeniX]

It's interference from your cell phone, or any number of other things. I used to have that way back on those old Nokia brick phones. Does this not happen unless your cell phone is sending/receiving and/or has it only recently become an issue? Hell, just having a smaller CRT next to your computer power-source can cause interference. Or powered speakers (especially those with an external amp).

If it happens all the time: It might be time to retire the old girl. If it only happens when your cell phone is ringing, then it's not an issue.

[Elheru Aran]

It's fairly recent. It does happen occasionally when phone is *not* going off, but it definitely happens every time it does.

And yeah, it is probably time to invest in something with a higher resolution... My phone is a Samsung, but it's also a brick.

I figured it was the phone but it might just be the monitor.

How does that work anyway? The frequencies the phone uses mess with the CRT tube or what?

[TheFeniX]

I'm not en engineer, but I figure it has something to do with the frequency oscillation screwing with the scanning method of the monitor.... or whatever. Cell phones will also jack with speakers, but it only seems to be a problem right before ringing and the initial dialing. Might have something to do with the phone using a stronger signal in some kind of handshake with the cell tower, then switching to less power once the connection is established.

I used to answer my cell-phones really fast in the car or when in front of my PC. People who called me thought I was psychic because I could answer before they got a ring on their end because I already knew to answer it before mine even rang because my speakers would give me the heads-up.

All I know is this is "a thing" with CRT monitors. Just like magnets can pull the electrons in the tube around and cause all sorts of weird shit. Note: don't test the magnet thing, it can permanently damage your monitor.

[rapidsquirrel]

Probably something do with the RF frequency of the playing a bit of havoc with the deflection coils in the back of monitor. There is enough copper wire back there to pick a lot of interference from just about everything. I also can see it being possible given the age of the monitor, the deflection system not being as powerful as it once was and so being a little more susceptible to this sort of interference. Your brick of a cell phone is probably pretty noisy (at least in a RF way) when it's actively talking to a cell tower especially if reception is poor and it's transmitting at full power to compensate.

Reminds of my freshman year of college back when CRT's were still the standard, and I had to help a floor mate who couldn't figure out why her monitor was really wavy all the time. Long story short, the top of a monitors is a bad place for a fan.