High pitched humming noise out of speakers

By Scott88
Jul 1, 2007
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  1. Hello,

    To the one who offers help god bless.

    I own an HP Pavillion DV1540ca laptop that is just under one year old. At about 10 months of age, I started noticing a high pitched, irritating humming noise. What sparked it, I do not know. It is a piercing high pitched toned that is very consistent and the same note every time. It turns on when the laptop is operating at a higher level (eg. running a movie and an audio file at the same time). It is possible it is related to the harddrive spinning or the fan spinning.
    However, I do not believe the humming noise is a result of the an inefficient fan or rattling of the casing because when I plug my laptop into my sound system, the humming (unfortunately) comes out of those speakers too, almost proving it's not a rattling and maybe even a software problem.

    I sent it in 3 times through staples, 2 of which went to HP, none of which fixed the problem. Staples said they couldn't hear it (although upon start up I showed them the problem), HP replaced the fan the first time (and probably didn't test it...), and lastly, HP replaced the bottom casing, and the main board. All to no avail. I gave specific instructions on how to obtain the hum and I have gotten my laptop back 2 months later in the same condition in which I sent it in.

    Now it is Canada day weekend so contacting HP is out of the question, and I think I will talk to some real people who can help me out.

    Please offer any advice you can give. I'm beginning to wonder whether or not my laptop will be fixed before school begins again...

    Scott Nguyen
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,684   +153

    This hum could be comming from the internal DC charging circuits. Possibly from a power conversion circuit board
  3. Ph30nIX

    Ph30nIX Newcomer, in training Posts: 359

    I think what he is trying to say is a dodgy power supply unit (correct me if im wrong). Seeing as the mobo was replaced you can rule out the soundcard (most likely it was onboard). If you have any external peripherals try leaving them disconnected and just have the laptop, power and mouse if needed. Also try to hunt down a different power supply (or even just try running of the battery).
  4. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,684   +153

    You haven't worked on many laptops have you Ph30nIX...

    Laptops are much different than desktops when it comes to power. The external AC adapter turns your wall plug AC into 14 to 24 volts DC. This 14 to 24 volts DC is converted into the several DC voltages needed by the laptops internal circuits. Many laptops have a separate power board that acts as a power regulator. This board can hum or vibrate, causing a hi-pitched noise
  5. Scott88

    Scott88 Newcomer, in training Topic Starter

    Hello,

    Thanks for the replies so far. I tried disconnecting the power supply just in case, but I realized that when I got the hum back it was in my car coming back from staples. So again, the hum is still there.

    That's also with all USBs and peripherals disconnected. Still there and annoying as ever. Could it be a shielding problem between the fan running or the HD running and the speaker wires inside?

    Scott
  6. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,684   +153

    Hi Scott,
    as you said, this laptop has been dismantled at least twice for this hum. If you can hear the hum coming from the speakers, the hum is not a physical vibration. It is an electronic signal...

    Does the hum go away when the speakers are disconnected?
  7. Scott88

    Scott88 Newcomer, in training Topic Starter

    Hi,

    Electronics is what it is leaning towards. I am going to wage a bet that when speakers are disconnected, the humming will stop. I haven't yet because I am a computer "n00b", but if I can learn how to safely do it without having to saulder wires back I would be glad to try.

    Either the physical method, or is there a way to change the output of the speakers via control panel or something?

    Scott

    P.S. thanks.
  8. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,684   +153

    Laptop speaker assemblies are aways connected to the main board by removable connections. This hum could be caused by the speakers themselves. There is no need to solder or unsolder anything
  9. cnewhan

    cnewhan Newcomer, in training

    I have the same problem

    I own a dv1000 hp laptop and to make a long story short i had some friends over and did two things that night. The first was that i changed the equalizer on itunes so i could put up the music louder and that night by brother knocked the computer off of my bed... i have no idea what to do but i can contol the strength of the noise with volume keys on the computer. The noise only comes on when the fan comes on too. please help me. The noise can also be herd when i conect it tomy speakers and headpones. if you can tell me what i have to replace i would be very thankful. did you try and repace the speakers? somebody plea help me
  10. Scott88

    Scott88 Newcomer, in training Topic Starter

    Thankyou very much guys. Staples has agreed to replace my laptop.
    As for your problem, I do not think the fan etc is the route to go. I would first work on the mobo or the sound card or the speakers all together.
  11. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,684   +153

    If you have never worked on a laptop, I wouldn't start with this one. Sometimes just a simple disassembly and reassembly of the laptop is all thats needed... sometimes not. Take it to someone with experience working on Laptops/notebooks
     
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