Buzzling sound... from L797, causes ?

1. offizieller Beitrag

    Hello Prad.


    Today I got my new L797 (1200 €). So far I am happy with it, no dead pixels. But Idiscovered one little issue.


    There are some low buzzing sound from the right upper back side
    (propably the power supply). What could be causing it, it disappears when the screen is Powered On without graphic signal.


    I use DVI, have a Intel Celeron and some Intel MB Chipset and a "PCI" Inno3D FX5200.


    The manual says it supports 60 and 75hz, I cant change the refreshrate
    to see if it helps. Is the 75hz something that the card must support.
    IS it normal that TFTs have some little "noise".
    I listened to all the TFTs in school. 15" NEC 17" Dell and more, couldnt hear any sound at all. My friends 19" (samsung, dell, iyama) they dont have any noises.


    I be beack with any news if I solve this. Hops this isnt a service issue.
    I have barely played with i tmore than 5-6 hours.
    Dont want to send it for repair, unless it is hardware related malfunction.

    • Offizieller Beitrag

    A lot of displays have this high frequently noise. Some very low and other louder. Do you hear the noise with 100 % brightness also? Are you sure that the display supports 75 Hz digital or only 75 Hz analog and 60 Hz digital? Please check the manuel again.

    Oki.
    Bit should I expect this problem from a 1200€ TFT?
    Ok if it appears on a less advanced modell.
    But the L797 is the state of art/cutting edge 19" TFT-monitor today.
    Shouldnt I get a noise-free TFT for those money ?


    What I am scared of is if I send it back I get one complettly noise-free but maybe with 2-3 dead pixels. This noisy L797 I have now have none-dead pixel (acc. to Nokia Test). I could ask for a silent TFT from Eizo-support
    but not for one with no dead-pixels ( Eizo have the ISO-xxxxx policy too)


    Maybe I call Eizo in Sweden and ask for a replacement unit.
    If the new unit have "NO" issues" at all I take it. But if it have
    like dead-pixels, what should I choose then,
    the noisy one or dead-pixel one.

    You was right about the backlight setting.


    This sound only exist when the backlight is set at lower than 100%.


    Is it some kind off technical limit.... but hallo world we are in 2005
    shouldnt problem like this be solved today?



    Any known methods today to minimize the sound?


    I havent connected the computer ot the TFTto a grounded outlet, will it help with grounded outlet?


    I must use the custom setting 50% at 6500k or the Text mode
    45% 5000k when i sit for a longer period. otherwise I cant use the TFT more than max 1 hours with 100%.


    Can you recommend any good mixture of 100% backlight, , gamma, white-temp and more.... ?

    The buzzing sound is because of the PWM dimming of the backlight. Some kind of modulation of the power supply for the cold cathode lamps. The modulation frequency is done at low frequencies and therefore you can hear it. Thats just plain physics. Its basically an electro-mechanical problem affecting all magnetic components and can vary a lot even for the same monitor model.
    All manufactures know that of course!
    There are technical solutions to reduce audible noise but its expensive. 'Cause we are in 2005 cost is a big issue expensive solutions are avoided.
    As longs its not featured you have to live with buzzing sound. BTW this is true even for Plasma and LCD TV sets which are way more expensive.
    Buzzing is everywhere. Only when customers keep complaining about it it might disappear.


    Monitors which use analog dimming are buzzing free. Usually you'll find analog dimming in cheap monitors. The drawback of analog dimming is that the back light changes its white point and the dimming range is quite small.

    • Offizieller Beitrag

    I would call the Eizo Service. If the Sound ist to loud, ask for a new one.

    Yes I did so, I call Eizo and they sent me a new one.That one have a little louder sound in non-100% backlight mode and...
    a dead green pixel in the middle.


    Eizo kindly dead-pixel policy says black or white pixel in the middle will give a exchange unit. But not a green one.


    So My choice is down do:


    1.) Buzzing model, with no dead pixel, a little loose frontframe.
    2.) Buzzing, green pixel in the middle/middle, good attached frame.


    Because the 2.) is within the ISO xxx-02 policy I cant get a third choice.
    I think I stay with the 1.) can allways use music or dont turn the head against the TFT. I can use tape to fasten the front frame.
    Besides the the sound wont kill me, but bothers me more physically because I will allways think what i paid for it.


    But next time I will buy one that could have complettly lousy specs,
    just hopr it is silent in any setting with backlight!