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Discussion Starter · #1 ·
Hello everyone,


I have a Vizio E421VA that is not getting sound through the built-in speakers. The only sound that comes out is a very subtle high-pitched noise that disappears when the volume is turned all the way down or on mute. That high-pitched noise is constant when the volume is on, no matter what is playing on the TV. I've opened the TV and thought I could try testing the speakers with a AA battery to see if it makes any static, and it does, so it seems the speakers themselves are probably working. I've tried playing music from my laptop with it connected to the TV via an AV-headphone cable without success. After reading someone's suggestion, I tried connecting a soundbar to the TV via the optical sound jack and that DOES work -- sound from the TV comes out of the soundbar without any problem. After researching online, a lot of things are pointing to the sound amplifier/IC? I don't have much experience with fixing TVs but would like to try to fix this myself, if possible. However, I am having trouble finding any resource that points me to where the sound circuitry is located on the board. I'm hoping to find that the part is burnt or getting too hot or maybe has cold solder joints. Nothing appears burnt from what I can see and none of the caps appear bulging, but there are a couple of heatsinks that may be hiding something.

At the very top edge of the board in the picture, 1/3 of the way from the right, there is a white connector adjacent to 4 black vertical-standing caps in a row -- that is where the speaker wires connect. There is a heatsink directly south of that row of caps which is soldered into the board via 2 metal rods. Could the sound IC be located under that heatsink?


I apologize for my ignorance with TV circuitry but would like to fix my TV sound and appreciate any help/direction with this. (Please be as specific as you can, even better if you can circle the location on the picture if you can). Thanks for any help!


P.S. The soundbar is borrowed and not mine, so I'd like to avoid buying a soundbar if it can be helped. It'll also be more gratifying if I can get it working again. =)

cbpftxacb5k00808.jpg 1009k .jpg file
 

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Discussion Starter · #4 ·
The TV is a few years old but still good. It is out of warranty unfortunately. Thanks for the website, hopefully the problem on the board can be narrowed down.
 

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Discussion Starter · #5 ·
Yeah, I checked to make sure the speakers are on in the TV settings. I tinkered with all the settings I could on the TV (turned speakers on/off, changed the speaker balance to left/right, turned off surround sound and the other special sound features). I've also tried resetting the TV to factory setting a couple of times and did some other suggestions that worked for other people like unplugging the power and holding down the power button on the TV, which I guess is another way to reset it. Also, none of the wiring inside the TV appear loose to me -- I unplugged/plugged some of them to make sure.
 
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