Everytime I turn my computer monitor on or off, I hear a series of loud clicks and pops. What on earth is it doing. Thanks
Also, last night, after I turned my computer off, and went to bed, I turned all the lights off in my room, and low and behold, the monitor was glowing. It was off (ie, it wasn’t in standby), the actual screen it’s self looked like it was glowing, what caused this.
Thank you in advance for your time and consideration.
I know that some of the clicks are the result of your monitor’s degaussing function in operation. Most modern CRT monitors I have seen degauss automatically upon powering up. You can try degaussing your monitor now and you’ll probably get some of the sounds that are made when you turn it on.
Read this to familiarize yourself with how CRTs work: http://entertainment.howstuffworks.com/tv6.htm
The screen continues to glow after you shut it off because the phosphors still have some charge left. They’re like glow in the dark toys. The toy’s phosphors are energized by light and release the stored energy, but not rapidly. Turn off the lights and you can still see the toy’s phosphors releasing its energy.
You’re welcome.
Don’t forget also that the screen gets a static charge when you turn the monitor on. The sound you hear are multiple mini discharges across the screen. If you run your hand over the screen just after you turn it on, you’ll hear more of the same.
Also, when you turn te monito off, a lot of things that heated and expaned while the monitor was on, are now condensing and “popping.” Much like the sounds you hear from your engine after you turn it off.
The technical term is Schizophrenia.
4
WTF schizophrenia?
also, what does Deguass Do? Please give me more than it demagnitizes the monitor. Thx
When an electronic device clicks it’s usually a relay doing the clicking. Relays are precursors to transistors that are still used sometimes, especially in high-current situations like a monitor, and when you need a simple on/off rather than a gradual gain.
It’s a coil of wire (inductor, electro magnet, whatever you want to call it) wrapped around a bar that’s free to slide back and forth through the coil. When current flows through the wire, a magnetic field gets set up and flings the bar one way or the other. The relay is set up such that the metal bar can close a switch when it’s flung in one direction, and opens the switch in the other direction.
The clicking sound is the metal bar slamming one way or the other, breaking or closing the circuit.
I just did a lot of reading to post this answer. It ain’t a short one… but I was curious too, so what the hell.
Basically there are 3 main componants sitting in fron of your face. The glass, the 3 colored phosphors behind the glass (that light up) and a piece of metal called a shadow mask.
Quote from one of the sites I was reading;
“The shadow mask is a metal grillwork that allows the three electrons beams to hit only specific phosphor dots on the inside of the tube’s front surface. That way, electrons in the “blue” electron beam can only hit blue-glowing phosphors, while those in the “green” beam hit green-glowing phosphors and those in the “red” beam hit red-glowing phosphors. The three beams originate at slightly different locations in the back of the picture tube and reach the screen at slightly different angles.”
Anywho, the shadow mask has to have the same thermal expansion characteristics of glass (so the glass and the grillwork are perfectly alligned at all times, regardless of heating and cooling) and aparently the metal used is called Invar. This is a metal that magnetizes easily. And since moving, charged particles are deflected by magnetic fields, the electron beams that light up the phosphors are being deflected and hitting the wrong phosphors.
Just imagine 3 guys with red, blue, and green paintball guns (electron beams) shooting at red, blue, and green targets( phosphors), respectively. Red shoots at red, blue at blue, etc. (mind you my lovely example excludes the fact that they should be shooting each through color specific holes in a metal wall in front of them, but I think you’ll follow without it)
This is how a normally functioning monitor behaves. Now we bring in the magnetic field. The magnetized field will cause mr red paintball gun to shoot at the blue target sometimes, causing a purpley color, thus distorting the color of the target. Same thing on your monitor. Sometimes red is red, but othertimes it’s purple or whatever.
Degaussing, which gets rid of the field, causes them to be straight shooters once again. YAY.
Also, in case you were curious, the process of degaussing is exposing a magnetized item to fluctuating, and ever decreasing, magnetic fields.
another quote
“To demagnetize the shadow mask, you should expose it to a rapidly fluctuating magnetic field that gradually decreases in strength until it vanishes altogether.”
I hope that’s enough. I read like 5 different web sites, so if you want cites, there weren’t any concise ones to choose from.