Hi all,
You may get some help from the dealer if it is under warenty.
Hitting is not recomended, it makes you feel better but it won't help the problem and might make it worse.
What you hear is a sympathetic vibration caused by the magnetic field that produces your horizontal sweep.
A part of the coils in your yoke are moving and yes it will drive you crazy.
Don't try to smother it with a blanket as those vent holes aren't just there for decorations.
I don't recomend taking the back off and turning it on to find the noise either as it is likely inside the coils of the yoke and there is HIGH voltage present.
15 to 20+ KiloVolts depending on the size and make of the monitor.
That will definatly get your attention!
If you try adjusting the refresh rate go lower than optimal never higher or you might need a new monitor quicker than you think. Like now!
The good part is it will likely work fine for a long time.
The bad part is it will likely work fine for a long time.
A new one will fix it!