Monitor flickering

Factual Questions
1

Alright, I’ve got a problem with my monitor flickering. I’ll lay down the facts, and let you analyze them.

It begins flickering sometime between 6 - 6:30 PM, everyday. In the morning, if I wake up and turn it on, there’s no flickering at any resolution.

The flickering is time related; if I leave my computer off the whole day, and turn it on at, say, 6:30PM, it will already be flickering. Length of computer uptime makes no difference, it alternates between flicker and non-flicker. Thus, it is probably not some sort of defective capacitor build-up in the hardware or something.

I don’t know what time period it goes from flickering to non-flickering, it happens when I sleep. Sorry, I can’t afford to stay up all night waiting for the transition.

There are no appliances running (at least, in my apartment), that would cause flickering. In other words, I don’t turn anything on or off at this time. So, fans, washing machines, etc. are not the cause. It doesn’t rule out appliances from other apartments though.

It is not a driver problem, the flickering will be present even in the bios screen, or any operating system I might run.

The monitor does not flicker, even after 6:30, at 75Hz, if plugged into my friend’s computer. It should be noted that it’s plugged into a different outlet though. I have not yet tested another monitor on my computer.

The flickering developed after I moved into this apartment, which was about three weeks ago. I have had the same computer setup since May of this year. I’m using a Radeon8500LE and a COMPAQ MV740 monitor.

Those are the observations I’ve made thus far. I am aware that there are more tests that I can do, and I will do them when I have time. (I don’t exactly have spare monitors and video cards growing on trees here, nor the time to test out every possible variable)

Anyway, from the above information, my theories are that perhaps

  1. someone in a nearby apartment turns on some interference-generating appliance between 6-6:30 every day, like clockwork. Or,
  2. that maybe at this time the outlet is no longer giving out enough energy to properly power my video card for the higher refresh rates (perhaps related to heavy appliance usage after peak hours?)

If anybody can help me on this, it’s gonna be one of you guys.

2

If you’ve ruled out refresh rate, I have a few things to try. First run an extension cord from the other outlet to the normal monitor location. Does that make a difference? Run a extension cord from normal location to friends computer, does that make a difference? This may help you figure out if it’s the outlet or the location. Is it near a wall that is shared with another tennent? If the other person has something with a large electromagnetic field coming out of it, that will make a difference. A large speaker, TV, or a furnace blower motor maybe. I’m not sure what else to say right now, except to try those two things and determine if it is becuase of the location, outlet, or neither, and then go from there.

3

Mine flickers at odd intervals. Sometimes it goes dark (like the pre-powerdown “sleep” mode). I have to whack it to get the screen to go black, then power down/power up. If I don’t whack it first, it won’t turn back on.

4

It sounds to me as if it could be some kind of magnetic interference in your appartment. Esecially the fact that it seems to be linked to an outside event.

When you say that the monitor does not flicker with your friends computer, was that in your appartment or elsewhere?

Have you tried moving the PC around? Try putting it in another room, or bringing the entire setup over to your friend.

If it turns out that there is magnetic ‘noise’ in your appartment, there’s not much one can do. Electric fields are relatively easy to shield (tinfoil hats:)), but to protect from a magnetic field is more difficult, especially if it’s low frequency.

It’s possible that there is some kind of electric device that goes on in the evening, that draws a large current, that is not led back properly. (This can be a problem with big installations with multiple ground paths.) If the offenting machinery is identified it should be possible to reduce its emisions by putting ferite chokes on the power leads, to force the current back through the proper path instead of some other ground.

I have a similar problem, when the screen flickers as soon as a train passes by. I’ve been thinking of getting a TFT screen, as they should be less sensitive to magnetic fields.

5

Look at the back of it, there is a model, manf & date stamp, give me those.

6

Well, I moved the monitor from the desk onto the floor, and lo and behold, it stopped flickering. So it would seem that the flickering’s caused by interference from the next-door apartment. Are there any solutions? (Other than moving the monitor, digging up the wall, or having to confront my neighbors)

7

What the hell does that have to do with anything?

I would put bets that there is some sort of strong magnetic current in the wall next to your monitor (do you have central heating? does it turn on automatically? If so, when? )
to test tis try and move the monitor away from the wall. try and rearrange your desk and see if it still flickers.

8

If the flickering stops after an hour or so, I would guess it is very likely the neighbor cooking dinner. Microwaves can do a number of monitors, so can toaster ovens for that matter. Actually, there are all kinds of stuff in a kitchen that could be the culprit.

If it keeps flickering til bedtime or pretty late in the evening, I would guess it is a fan (ceiling fan even) or an entertainment device (radio, TV, or even another computer).

9

Is the 6 - 6:30pm time frame around dusk where you live? If so, could there be a outdoor light with a light sensitive starter nearby? A sodium or mercury vapor light ballast could generate enough of an EMF field to interfere with your video display as well.

You might also check for two-way radios in the vicinity. We used to play games at one of my former employers offices by walking around and randomly keying the walkie-talkies (big ole honkin’ Motorolas) which would make any video display in about a 6’ radius go nuts.

Just a couple more things to look for.

10

Well, I was hoping for a solution that wouldn’t require moving my computer and desk somewhere else (as it is in the ideal spot right now, with the exception of the flickering.) Essentially, this means trying to shield my monitor.

11

I usually hit the top of the monitor lightly & if it doesn’t flicker anymore, it’s a loose joint inside or a loose connection in the back. The fact you picked it up & put it on the floor would redo the connection in the back & it may work again.

The reason for asking the date of manf & model is to see how old the monitor is & if its common with this one.

12

I’m pretty sure it’s not a loose joint, I’ve already tried hitting the monitor (lightly, of course!). De-gaussing doesn’t help either. Besides, would a monitor develop a loose joint between 6-6:30 every day, like clockwork? It’s gotta be interference from something.