fabio656 ha scritto:
LUIR37, se senti il Buzz addiritturaa 2 metri di distanza anche con volume della tv acceso, hai preso un tv difettoso.
il mio tv in firma ha il buzz (come già detto, normale x i plasma) ma per sentirlo devo mettermi con l'orecchio dietro il tv togliendo tutto l'audio.
se tu lo senti a metri di distanza, riportalo indietro.
penso invece che sia un problema che la Samsung sottovaluta solo perchè dà fastidio ad alcune persone e non a tutte, ma è un difetto molto grave come si vede dalle numerosissime segnalazioni di utenti con questo tipo di problema nella sezione in inglese del forum avs:
http://www.avsforum.com/avs-vb/showthread.php?p=19718727
Well it's been 2 months and my ordeal with my buzzing PN58C8000 has finally come to an end. Hopefully this information will help fill in some missing information to everyone who's been dealing with this issue.
In that time, I've been through two versions of that set, met personally with the Quality Control rep from the Samsung plant in Tijuana and visited 3 different stores to try and find ANY thin-panel Samsung plasma that doesn't buzz.
When I met with the QC rep in November he acknowledged hearing the buzz from 15' away in our living room. He removed the back panel and replaced the center board which is the power supply (SMPS). That did nothing. While the back was open we held our ears against the different components to see if any one thing was making noise, and we noticed something very interesting...
Now I'm not an engineer but I truly believe it's the inductor coils making that noise.
From the back there are 3 large circuit boards - one SMPS power supply in the center, and a video processing board on either side, one X and one Y board. There are 2 inductor coils (they look like copper donuts) attached to the left board and one on the right-hand board. The coils are located about 1/3 the way down and in from the top and sides respectively. Trace your ears around this vicinity from the back or front and you might notice this is where it's the loudest.
In my cursory research I stumbled upon a phenomenon called "coil noise", a somewhat common occurrence in computer video cards. Inductor coils are like shock-absorbers for the power signal and they can make noise when they vibrate. (Feel free to Google homemade remedies for reducing coil noise)
So if I had to guess, the inductor coils are vibrating and it's resonating with the glass that's then acting like an amplifier projecting the sound directly forward. From what I've read Samsung removed a sheet of glass from the design to reduce the depth, and combine that with the need to compress all the components as close as possible to fit it into that frame. So the basic design is flawed, at least in my opinion. The QC rep even tried installing rubber washers between the circuit boards and metal frame but that also did nothing to reduce the buzz.
This is likely why virtually every thin-panel Samsung plasma made in the last 2 years has the same issue. They could easily be using the same exact inductor coils from model to model. I've personally heard buzzing in samples from the 8000, 7000, 6500, 550 and 650 plasma models in quieter showrooms.
For reference I also listened to a comparable LG plasma and 2 different Panasonic 58VT25's, all of which are traditional 3+"-depth designs. Those have what most would call the typical "plasma hum" but that is slight in comparison to the Samsung's buzz, and are almost completely inaudible from beyond 1-2 feet.
If you were lucky enough to get a non-buzzer it could be happenstance that you ended up with a sample installed with coils that were made with slight variances that don't vibrate as much. It also explains why some may buzz more than others - i.e a set may have been installed with one or two quiet coils but still got one or two noisy ones.
UNFORTUNATELY - Samsung still considers these buzzing sets to be in spec, so don't expect any help from them. They indicated they are working to resolve this issue for future models, but considering the 2011's will likely be unveiled at CES next week it's doubtful any improvements have been made. We shall see.
So if you're reading this and considering getting one of the remaining 2010 models or one of the new 2011's, please proceed with caution and make sure your store has a good return policy.
And in case you're wondering how my journey ended - the 58VT25 doesn't look so bad in my setup.
se ti metti con l' orecchio attaccato al retro della tv ovvio che il rumore ti rimane nella testa comunque,è anche un fattore "psicologico"..
