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Discussion Starter #1
Hello everyone, I have a problem that no one seems to get.

Everyday when the street lights turn on, my computer and my TV start making a whirring/buzzing sound, I dont really know how to call it. The noise is louder when either the TV or computer are on, but they still make the sound when they are off too. All these stops at dawn, when the street lights go off.

I have recorded the sound HERE, it is not the ambient sound, it is the high pitched one.

The noise is loud enough that I can listen to it clearly when I play soft music for example.

I have done some research about this and I found out that street lights can mess up the harmonics, I can see our buildings power cable comes from the same pole where a street light is right in front of our house.

To be true I have no idea why this happens, but it just doesn't sound right at all and I am afraid it can damage my TV or Computer.

Please help me!:eek:
 

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Does the noise come from the speakers, or from inside the box with the volume turned all the way down also?

You might try a noise reducing surge protector power strip (glorified extension cord) to plug the computer and television into.

You might try improving the grounding. Get a long (bare or insulated, #14 to #18 gauge) wire and daisy chain it from one piece of equipment to the next. For the computer, attach it to one of the screws that holds the back cover in place. For the television, attach it to one of the stud jacks in back for left/right audio or composite video (yellow). Connect the far end of the wire to a known ground. For the latter you might get away with a radiator or a water pipe or the screw that holds a receptacle cover plate on but a sure shot is down the basement stairs to the electrical panel or the fat bare ground wire coming out of that.

Note that plug in noise reducers (that "clean up" "dirty" power) draw some power 24/7 unless unplugged. The harmonics that get filtered out are dissipated in a manner not too different from running a light bulb or heater and that counts as billable power.
 

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Discussion Starter #3
Does the noise come from the speakers, or from inside the box with the volume turned all the way down also?

You might try a noise reducing surge protector power strip (glorified extension cord) to plug the computer and television into.

You might try improving the grounding. Get a long (bare or insulated, #14 to #18 gauge) wire and daisy chain it from one piece of equipment to the next. For the computer, attach it to one of the screws that holds the back cover in place. For the television, attach it to one of the stud jacks in back for left/right audio or composite video (yellow). Connect the far end of the wire to a known ground. For the latter you might get away with a radiator or a water pipe or the screw that holds a receptacle cover plate on but a sure shot is down the basement stairs to the electrical panel or the fat bare ground wire coming out of that.
Hello Allan, thank you for your quick response.
The sound is still noticeable even when the computer and/or TV are completely off. The only way to get rid of the sound is unplugging them from the outlet.

About the grounding, I wonder if that is possible given that this is quite a brand new apartment. Also, the computer I have is an iMac so there are no screws or any way to get into the internals. The sound, however, comes from the bottom left side which is where PSU is located, the TV too doesn't have an external transformer so I guess it must be inside where the sound comes.

I will try to find one of those noise reducers/surge protectors and give it a go, are they expensive?

Thank you.
 

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Definitely a power line harmonics problem caused by the street light ballasts. You might try plugging the equipment into a good on-line UPS, which should completely isolate it from the line noise. You also might try contacting the power company. They may provide a filter to fix this.
 
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Discussion Starter #5 (Edited)
Definitely a power line harmonics problem caused by the street light ballasts. You might try plugging the equipment into a good on-line UPS, which should completely isolate it from the line noise. You also might try contacting the power company. They may provide a filter to fix this.
Hello, I think too it is a problem with harmonics. I have been looking for an on-line UPS, the problem is that on-line ups are just too noisy 45db and up. That is just too much. Besides that I cannot find a device that can filter the harmonics. I called the power company already, they sent a guy who said never heard of something like this (which I believe) because he said he couldn't listen to anything! The sound is kind of high pitched and I can hear it very well at use-distance from the computer.

How about a surge protector with some noise filtering? Would that help?
When I google "Harmonic Filter" in google, only industrial ones appear... am I doomed? T-T
 

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I'm pretty sure the power company has to fix this. Ask them to send a tech to look at the pole or you'll have to speak with your state Public Utilities Commission.
 

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Call the POCO asap and let them know excatally what you going thru with the street luiminaire and they should have someone send out and check it out.

I am pretty sure the ballast is about halfway toasted or the HPS* ingitor is stuck on pulseing so that you can heard on your speakers which it may be cased by high voltage spikes on the luminarie.

Merci,
Marc

* High Pressure Sodium ( it will throw out orange colour which it is a common street luminaire )

Merci,
Marc
 
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JOATMON
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Hello, I think too it is a problem with harmonics. I have been looking for an on-line UPS, the problem is that on-line ups are just too noisy 45db and up. That is just too much. Besides that I cannot find a device that can filter the harmonics. I called the power company already, they sent a guy who said never heard of something like this (which I believe) because he said he couldn't listen to anything! The sound is kind of high pitched and I can hear it very well at use-distance from the computer.

How about a surge protector with some noise filtering? Would that help?
When I google "Harmonic Filter" in google, only industrial ones appear... am I doomed? T-T
I don't know of any surge protector that will filter harmonics. You get minimal filtering with caps.....it really takes an inductor coil to filter out the high freq stuff.

As for UPS's....unless you spend $500 or more, the lower end models (which are still good devices) do not filter out line noise in normal mode. In other words, if your power is not in a brown out condition or off, then the AC power bypasses the inverter in the UPS. It's only when you go on battery power that things get cleaned up.

With that said....it's worth having a UPS on your computer. The surge protection in them are typically much better than your Wallmart surge outlet strip.

This is what I use at home.....



The one I have is good for about 15 min computer time....I think I paid $75 for it....if I kill the computer....I can power a CFL light for more than an hour.....if you don't mind the beeping....
 

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Not exactly on topic but power line interference can be difficult to remove particularly on circuits providing large current draws. A "choke coil" can be put in line (in series) with the load to filter out most of the higher frequency noise. Also capacitors are placed across hot and neutral and/or in parallel with the coil. With both capacitor(s) and coil(s), we have a "tuned circuit" that passes the 60 Hz power with little loss but more loss compared with a straight wire and enhanced although still not perfect blocking of other frequencies.

The college I attended had a central clock synchronizing system (by Simplex) that injected a high frequency tone into the power lines. (It was for a few seconds every hour.) The college had its own substation and the tone was injected there. The tone was heard in most audio equipment and even from some light bulb filaments and some electrical equipment in every campus building and also in a few homes and town buildings near the substation. Several unsuccessful attempts were made over the years to eliminate the tone from the campus radio station broadcasts.

Incidentally, in earlier years the college radio station broadcast its signal via power lines rather than over the air. A radio placed near a power line, including wires in the wall daisy chaining from one receptacle to the next, would pick up the signal.

I do not think that the spurious frequencies would cause damage to computers and modern electronics. The power is rectified (converted to direct current) before being used by the circuits, and the filtering contained in the power supply removes a much greater percentage of higher frequency ripples when performing the needed function of smoothing out the 60 and 120 Hz ripples coming from the rectifiers proper.
 

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Discussion Starter #10
Thank you everyone so far for your replies, it makes me feel like I am not alone... Before I made this thread I spent whole week and a half researching about this problem and I couldn't find much if anything at all...

Unfortunately my problem still persists and dealing with the electric power supplier isn't going well.. (I live in Korea and I dont speak the language very well.. T_T). So tomorrow I will be going to check some on-line PSU's and hopefully they wont be noisy, otherwise my wife won't let me buy it T_T...

So just to let anyone else on the internet who might encounter a similar problem, the solution is either get the Power company fix the problem or get an online PSU..

How about a line-interactive PSU? There are many flavours of those out there.
 

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Discussion Starter #12
Well, I've never had this problem before and I've been here for a while already.. Recently I bought this house and discovered this problem. In any case, it is not bad for the equipment right? It's just a bit annoying... Or, is it harmful? :( I am scared if my computer will fry one day T_T
 

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JOATMON
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Your computer uses a switching power supply. To some extent, it puts out as much noise as that HPS light. But what will fry it are voltage spikes. At a minimum, I would make sure you have a quality surge protector on it.

Same for any other high $$ electronics (TV, Stereo, etc)
 

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Discussion Starter #14
Your computer uses a switching power supply. To some extent, it puts out as much noise as that HPS light. But what will fry it are voltage spikes. At a minimum, I would make sure you have a quality surge protector on it.

Same for any other high $$ electronics (TV, Stereo, etc)
Yes, in any case I will get an off-line UPS + Surge protector. Thank you!
 
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