Absolutely. This TV is buzzing.
It’s not directly in front of the wall. It’s about a foot from it. The buzzing volume does not change with TV volume. Sometimes the buzz gets louder for a second when there’s a scene change. Sound fixable by somebody with little TV repair knowledge such as myself?
Acck! Flyback transformers! I hate them things! I had a TV with a fatal flaw of the flyback being set too close to something else and within a few months, the flyback would go bad again. Don’t think they’re used in flat panels though.
As for the OP’s problem, have you moved anything electronic near the TV? Something that isn’t shielded properly could cause interference with other devices.
Any new taxi companies or the like in the area? I remember the days when I knew where every taxi in my area was going and as I’m near a major airport, used to sometimes get transmissions from the tower over my TV and radio. It could be an outside source that is causing the distortion, in which case, you’ll probably hear it over a radio also. Another possibility is a neighbor with a new toy - walkie talkies or shortwave radio but that wouldn’t likely cause a 24-hour problem.
Nothing like CRT based sets. We don’t take any special precautions.
This noise is NOT coming from the speakers, right?’
As the buzz changes during scene changes, we can pretty much rule out the panel inverter.
You pretty much have run the TV with the back off and try to locate the noise source. I use a non-conducting tool to apply pressure to suspect parts on thepowersupply board. (this is the board which the power cord goes to)
If you can narrow it down to one part, remove the power, and apply hot-melt glue. This sometimes works. Sometimes, we replace the whole PS board.
There are dangerous voltages present while the set is plugged in. Not knowing what your abilities are, I recommend you consult with a tech.
Cilassi: the only recent electronic device is a cable box I got about a month ago. It sits on a shelf below the TV, where the satellite box used to be. And no, no taxi companies nearby, but there is a bus stop. 
longPath: I’ve got sound hooked up to my receiver, which I’ve had for probably 25 years. I just switched off the speakers and the buzzing stopped. I’ll try hooking up to another receiver. Should be fun, with about 50 or so jacks and wires to replug, hehe.
Well crap, I replaced the receiver, still got the buzz. Disconnected the audio jacks and turned up the TV volume, didn’t hear the buzz. So I replaced the audio jacks, turned the receiver back on, got the buzz again.
So I guess it’s the audio out panel on the TV itself.
Why even run audio to the television if you use a receiver? Just hook the audio straight from the satellite or cable box to the audio setup and listen to that.
Also, what is your connection from the converter box to the LCD panel? If you’re running coax, kill that and set things up properly with a composite, s-video, or component video cable. RF conversions from converter -> coax -> TV can generate audio and video noise, and is just the wrong way to do things.
I can’t answer for the OP, but I do know one excellent reason to run the audio through the TV before sending it to the receiver: some TVs have a cool “captions on mute” option that turns on closed captioning when you mute the sound.
Sure, that’s useful. But the OP is running audio into and then out of the LCD, and monitoring the result. Its probably better (and may fix this issue) to run the audio to the receiver with an “RCA” cable, or even better a digital audio cable if the converter and receiver is equipped for that, and then running the audio back from the receiver (perhaps from tape monitor) to the LCD panel if desired.
How would that result in muted audio when the TV’s mute command is used, though?
For muting audio, this is essential the same setup in that respect – audio goes to the LCD from the reciever, and can be any volume including muted. Closed captioning comes from the vertical blanking interval of the video signal, and so should still be available from the cable box via any of the video outputs (composite, component, s-video, hdmi/dvi, coax[ick] ).
ETA: actually, I’m not positive that CC is sent over the digital interface, because I’m unclear if vertical blanking is still there (or simulated for this purpose); CC may be sent by other means, or not at all.
OK, I think I misunderstood your question in my post above. You’re saying, I think, that the viewer would press mute on the TV, and the audio wouldn’t mute because the receiver is playing the audio. Good point – the receiver’s mute would need to be used. On the TVs I’ve used, the audio out on the TV wouldn’t mute the signal sent to the receiver, so you’d still be in the position of mute not working for both devices. Having said that, I don’t know how the OP’s television handles mute for it’s own audio output to another device.
Ideally, you’d just use one device – the receiver – to monitor the audio, and to heck with the TV audio. This assumes that the receiver knows about center channels and can generate one for a middle speaker set right next to the TV. Then if you want CC, you just mute the (already silent) TV.
I still want to hear if the OP is using a cable box -> coax -> TV connection, which would be a Bad Thing.
That was it. I talked to a guy at Radio Shack and he said the same thing. For some reason, that never occurred to me. :smack:
No buzz anymore. 
So, I guess my theory about the power supply was off base.
Glad you got it fixed!
Fixing that created another snafu. The picture settings keep resetting to default after 10 minutes. I gathered from the pidgen instruction manual I need to adjust from “Movie” mode instead of Dynamic or Regular, but it now resets after 30 minutes. aaaaaaaaaaaaaaaaaahhhhhhhhh
What do you mean by “reset” ? Many sets have a “sleep” timer that you can set, for people that fall asleep watching TV and the set will turn itself off. Typical settings are 15, 30, 45, 60 minutes. Are you inadvertantly turning this on?
Secondly, some sets have a setting to go to “sleep” after an interval of no activity (activity being changing channels or audio volume). Is this somehow being set? Does the set think it should go to sleep because its not being fed audio?
Peruse the TV’s setup menus and turn off anything that looks like a timer with minutes, or labeled “sleep mode” or similar.
I think something happened when I moved the TV around. It’s got buttons on the side for Menu, Source, Channel and Volume.
Somehow I reset it to Shop Mode, which uses max contrast and 16:9 ratio. It resets to that setting after 30 minutes. I did some reading around on the Samsung forums, and they say it’s what dealers do so they don’t have to reset the TVs all the time after customers monkey with the settings.
The forums say to hold down the Menu button on the TV for 5 seconds, and that’s supposed to clear it. Hasn’t worked.
Try pressing Menu and Volume together (on the TV, not the remote.) That should bring up a menu where you can return to Normal mode.
You certainly are having more than your share of problems!
This happens to me every time I do a computer upgrade too, control-z. I have to make at least 5 trips to TigerDirect every time I add a new component.
The menu+volume didn’t work.
Can’t get my DVD player to work either. Anybody have a noose handy?
you can do a reset from the service menu. I can walk you through it.