My Sharp Aquos 32inch HDTV makes high a pitched buzzing sound that is constant but slightly random while watching TV. It's beyond annoying, and I noticed that it doesn't always do it (not everyday). Why would it make this sound once and while? My fear is that as the TV gets older this may become more frequent, and then it is going in the trash.
It's not too loud, but I can't drown the sound out by turning up the volume because it's just so high pitched!

I'm going to assume this sound is evident (when there at all) even if the sound system is muted and thus not a sound system problem.

If the sound is coming from the body of the display itself and thus mechanical, it sounds like a choke in the switch mode power supply has a loose winding or is causing some other mechanical movement.

Time to call that pesky repair man.


CS

It's so inconsistent, but when it happens it's like the noise old CRTs made but louder. Not quite a "buzz"... I am paying for best buy's extended warranty has anyone noticed this with there HDTVs?

Switch mode power supplies (found in just about everything nowadays that run off mains power) use high frequency "switching" and clever sampling & smoothing to convert the voltage levels to the DC required for digital circuits.

The sound you hear from CRT's (BTW, if you can hear it, you must be under 18 or thereabouts) is the line scan oscillator (erm, delving into the vaults on that one) running at about 15 khz, from memory.

[No. of lines per field X No. of fields per frame X No. of frames per second]

A mis - behaveing SMPS could sound just the same. Not common, but anything can go faulty.


CS

do you think that's what I'm hearing? The "Switch mode power supplies" -I live in an old house with old outlets.
One time I changed the picture adjustments (contrast and whatnot) and the sound stopped, that could have been a coincidence, but is there anything in the way HDTV display an image that could make sounds? It's almost like what hard drives sound like when they are thinking (random bzzzzz-bzzz).

Well, I can't think of anything else an LCD display could possibly have wrong that would give rise to audible noise.

I would have the power outlet checked to make sure there is no issue with faulty connections etc, but if that is ok, there is nothing else.


CS

PS. The equation I gave you in post #4 works out thus:

240 (NTSC?) X 2 X 30 = 14.4 khz (I wasn't far out)

Don't know if this applies, but I've got a TV that buzzed like the dickens, when I called, they suggested I turn the backlight to "bright", and sure enough the buzzing went away - turned out they shipped with the backlight turned down, and it resulted in something buzzing... turn the backlight up, no problemo...