I've noticed this on many different TV sets, widescreen and regular, although it seems to get louder and deeper in pitch with a bigger TV. The noise occurs on first supplying power or coming up from standby, before the screen comes to life. They are just ordinary old-style non-flat CRTs, no difference between brands or prices.
Come to think of it, the ancient CRT monitors in the school computer lab do it too...
2007-05-19 21:24:19 · 6 answers · asked by rissaofthesaiyajin 3 in Computers & Internet ➔ Hardware ➔ Monitors
It is the degauss circuit.
This dumps about 20 to 50 amps of current though a coil at the front of the CRT to produce a big AC magnetic field. This then rapidly decays to zero, taking the magnetic field with it.
It is done to remove any magnetic effects from the Earth's magnetic field or small local fields.
The circuit itself does not make any noise, but any loose metalwork near that coil moves when it is energised.
If you want to see what it would look like without degaussing, turn the monitor on, let it degauss, then turn it though 90 degrees (either way) and look at red, green, blue and white screens.
The other thing to be aware of for the degauss circuit is that if you do get you monitor magnetized, and one degauss hit is not enough, you need to wait 20 minutes for the degauss circuit to reset (a component needs to cool down) before it will be effective again.
2007-05-20 03:11:40 · answer #1 · answered by Simon T 6 · 0⤊ 0⤋
It may be big electromagnetic coils energising or it may be a 'degauss' function on power-up. If you have a monitor with a degauss button / degauss selection on the menu it makes a really nice 'TTHunggggggggg' noise when you push it and the picture goes all wobbly for a second as it wipes out residual magnetism in the CRT back end.
There are big coils in the high voltage section and in the field coils (the ones that scan the beam around to draw the picture)
2007-05-19 21:35:39 · answer #2 · answered by bambamitsdead 6 · 1⤊ 0⤋
Static boost on a photograph tube is very ordinary; you may in lots of circumstances hear the release -- a variety of 'shooshing' noise -- whilst the television is switched off. This static discharge is in lots of circumstances no longer adequate to do harm on your set. a matching discharge can happen whilst there's a unexpected alleviation in brightness point yet you do no longer in lots of circumstances hear this simply by fact the fee has a tendency to be dissipated slowly, nevertheless you may develop into conscious of it greater in very dry climate. it is likewise a threat that your homestead could be very dry, tremendously in the experience that your homestead has heat air substantial heating and is definitely insulated. if it is so which you may want to objective an test with a room humidifier and notice if that makes a distinction.
2016-12-29 15:02:27 · answer #3 · answered by Erika 3 · 0⤊ 0⤋
Charging the CRT to 30,000 volts may make the noise; there also may be a relay closing to supply power to the transformer. A lot of them automatically degauss when started. Some also make a clack noise when they switch resolutions.
2007-05-19 21:34:25 · answer #4 · answered by Anonymous · 0⤊ 1⤋
hi,,, its deguausing. meaning, its removing, neutralizing the screen from static and magnetic fields that remain on the screen. that way the colors and picture will not be out of aim and focus when its turned on. the sound u hear is the static electricity and magnetic field forces that cancels its other and making the metal frame around vibrate. this is the best simpliest explaination i can give u. :)
2007-05-19 21:37:48 · answer #5 · answered by charlie 5 · 1⤊ 0⤋
high voltage (HV) put your arm near the screen and feel the rush
2007-05-19 21:30:02 · answer #6 · answered by James H. Wadd 3 · 0⤊ 1⤋