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Laptop Charger causes buzzing noise and disturbance on TV Screen

Discussion in 'Hardware' started by asinha, Jan 28, 2010.

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  1. asinha

    asinha Thread Starter

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    Hi,

    I hope I'm posting in the rite place.

    So here's the situation,
    Laptop : Macbook White (2.4Ghz Dual Core)
    TV : SONY Bravia 42"

    I prefer working on a bigger screen, hence my laptop is constantly connected to the TV Screen. I use mini-DVI to VGA adaptor for Video and M-RCA to M-RCA through the headphone jack on my laptop for audio.

    When the laptop is connected to the charger, it causes a buzzing noise and disturbances (horizontal distorted lines) on the TV Screen:confused:. Disconnecting the charger completely stops all of these problems.

    So far so good but this is very inconvenient as I can only work on battery power:(.

    Is there a permanent solution so that I can keep my charger connected without getting these screen artifacts and buzzin noise from my TV?

    Some ppl have suggested an inverter but I wanted some reliable advise before I start buying anything.

    Any help would be appreciated.

    Thanks.
     
  2. arknorth

    arknorth

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    It depends on where the 'noise' is coming from - the charger, or the MacBook. You see, the charger itself would be to blame if it causes the issue if only plugged into the wall but not the computer. If it happens ONLY when the computer is also plugged into the charger, then it could be interferance caused by the computer's own battery charger, or even a bad connecting jack.

    There are ferris-coils that can be added to the end of cables (if you've ever had a scanner, and seen that large goider-like block near the jack end of its power cable/USB cable, that's a ferris-coil noise filter). They are known as an RF Filter, and they usually can be snapped over a cable - the problem is finding one.

    There could be another solution/issue. Are you plugging the laptop's charger into the same power jack as the TV? Are you sure the grounding of this jack is good? And, using something like an extension cord, have you tried plugging the charger into a different outlet?

    A-N
     
  3. asinha

    asinha Thread Starter

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    Thanks for the reply ArkNorth.

    Ok, so here are some other symptoms/observations.

    The noise and disturbance is only seen on the TV Screen, at the same time the laptop's screen shows no disturbance whatsoever.

    I connect all my peripherals through a spike guard. So the first thing i did was to eliminate the possibility of the outlet bein faulty by moving the charger around to different sockets across the room. The fluctuation did change to worse or slightly/unnoticebly better:( (surprisingly depending on the proximity to the TV:confused:), but did not solve the problem.

    I've tried new cables with no relief.

    So that leaves us with
    1. charger's bad
    2. interference

    Could u pls tell me a little bit more about laptop-battery-interference ?

    I use an add-on extension cable to connect my magsafe charger.It looks fairly insulated but let me know what you think.
    http://www.flickr.com/photos/paulbeattie/3928964768/

    I'm gonna try connecting this to a different TV screen today to see if TV-input-Port is the problem. Will post results shortly.
     
  4. arknorth

    arknorth

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    Okay - then I would then try the charger WITHOUT the surge protector, as it too could be the cause of the problem.

    As for the internal issue with the laptop, its not the battery, but the charging transformer for the battery inside the computer (otherwise, it would be doing the 'noise' all the time). Its not surprising that it would not be causing any problems with the computer's own screen - I've yet to find one that would, as everything should be properly wired there.

    Internally with the laptop, the two areas I would be looking at would be the transformer that charges the battery, and the jack that the external power plugs into. A check of that is easy enough - jiggle it a bit. If either (a) the jack seems loose or makes a buzzing noise, or (b) the interferance on the screen increases, there could be an issue with it. In either case, that would be a technician's repair situation, especially with a MacBook.

    Now, from what you described, you mention 'periferals' - what else is plugged into this system? Could there be any other devices that could be causing an electronic signal that the MacBook's power line is catching and feeding in through its power system? For example - I once had a dish TV system with a modem - it once took a lightning strike and caused a nasty humm through the phone lines and lines on the TV - once the phone line was unplugged, it stopped the noise on both the phone lines and the TV screen.

    A-N
     
  5. arknorth

    arknorth

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    BTW - there's another thing you could try - if the Mac is willing to work WITHOUT THE BATTERY INSIDE IT, try using it with just the external power and see if the noise persists. If it goes away, we may have found that it is the transformer inside the laptop, or a battery that is not long for this world.

    A-N
     
  6. Megabite

    Megabite

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    Sounds like a noisy charger.....have you tried using a different mains plug in the house...also could be a faulty earth in the house wiring
     
  7. asinha

    asinha Thread Starter

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    (Sigghhh)....tried the shimmy-the-jack method, no change, the jack seems A-ok.

    But have-2-say brilliant observation A-N with your modem experience...actually one of the peripherals connected is my wireless Modem (Lord hasn't smite it yet:D), I'm gonna try with n without the surge protector, peripherals & purely on power without the battery.
     
  8. asinha

    asinha Thread Starter

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    Thanks Megabite. Unfortunately, powers fine,..that was prob the first thing i did...get good ol pot'meter out to check power levels..all good. And yeah,..have tried different mains as well.
     
  9. Megabite

    Megabite

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    If you try it with another TV does the same problem happen?
     
  10. arknorth

    arknorth

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    You did mention that the interferance gets worse the closer you get to the TV. Another place that causes trouble is that RCA jack, which tends not to be the best shielded cable in the house. Have you a heavier RCA to RCA cable to try?

    A-N
     
  11. sumitghaiin

    sumitghaiin

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    Hi all,

    It is really helpful post. I am also facing the same issue.

    I plugged ACER laptop 5920 charger to surge protector and plugged surge protector to different wall socket, lcd buzzing noise is less now.

    I still struggling for the solution.


    if I use Dell latitude d630, there is no noise at all. There is no noise problem frm ACER laptop if I use external speaker. There is buzzing noise only if laptop charger connected to wall mount.

    I appreciate your help.

    Thanks a lot
     
  12. asinha

    asinha Thread Starter

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    Lot of tests....still no joy:(

    1. Removed the battery and ran it directly on charger...problem persists.
    2. Removed RCA Jack connection (battery's still out)....problem persists. Replaced the cable with a new one...still the same.
    3. Tried it on a different TV..same problem persists there.
    4. Disconnected all connections to the TV (VGA Cable, RCA Cable)...the moment I connect the charger (charger's on a completely different socket as the TV), can see slight fluctuations on the TV:confused:

    Eliminating all of these scenarios, the problem areas seem like:

    1. The Apple Charger
    2. The barber-hating lady from "The Grudge":D
     
  13. arknorth

    arknorth

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    Sounds like that lady is causing all sorts of problems ;)

    Its either the wall charger or the transformer inside the MacBook. NOW, the only way to determin which it is would be to find a second charger and see if it still persists or drag out an ocilloscope with a magnetic field reader - BUT, there is a cheap-and-dirty one available in almost every house... really.

    The way you say that it causes interferance, the amount should be high enough to cause noise on other things like a cordless home phone - preferably analog (not digital) and not a cell phone. What you do is (with the phone playing the dial tone) run it along the power cord FROM the wall TO the laptop and listen. Depending on where the noise is worst should show you just where the actual interferance is coming from.

    Yea, its odd, and it might not work (since it could be too high a frequency).

    A-N
     
  14. polithium

    polithium

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    Sorry for posting to a slightly old thread, But I had this issue last night with my laptop and my girlfriend suggested it could be an earth loop issue ( http://www.jaycar.com.au/images_uploaded/humloop.pdf ), so in my insane bravery I removed the earth pin from my laptop power supply with some side cutters ( not a suggested practice by any means ), This did indeed work.

    You can get power supplys for laptops that are not designed to have earth attached, this should solve this problem in a much safer way.
     
  15. aka Brett

    aka Brett Banned

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    Good find(y)
     
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