Craft Tested by SW Hammond
Vizio Soundbar Won't Turn On? Replace The Capacitor – Vizio S4251w-B4 No Power Repair
Vizio Soundbar Won't Turn On? Replace The Capacitor – Vizio S4251w-B4 No Power Repair
Written by
SW Hammond
Published on
05 July 2025
Is your Vizio S4251w-B4 soundbar dead? I’ll show you how to fix it by soldering a $10 capacitor (470uF 16V) in about an hour. This common issue fried my soundbar twice, hinting at a deeper power supply problem, but this repair keeps it running. No advanced skills needed! Craft It, Rig It, Rock It!
What You’ll Learn
- How to spot a faulty capacitor (C21) in the Vizio S4251w-B4.
- Step-by-step disassembly and capacitor soldering.
- Tools needed: screwdriver, soldering iron, snippers.
- Testing the repair safely before reassembly.
- Why the capacitor keeps failing (power supply issue).
Tools and Parts Needed
Note: This fix addresses a common Vizio S4251w-B4 power issue but may recur due to power supply problems. Basic soldering skills required. As an Amazon Associate, I earn from qualifying purchases. Here’s what I used:
Transcript
is your soundbar broken completely failing to turn on this seems to be a common problem with the vizio s4251w-b4 it's a 5.1 surround sound system that has a wireless subwoofer and wireless rear speakers [Music] this problem has actually happened to me twice on the same sound bar i've done this project two separate times now because the sound bar continues to break there's a good chance that there's a more significant issue going on with the power supply as i keep frying the same capacitor to me this suggests that it's not a cheap or weak capacitor problem but more juice is getting sent to the capacitor than is supposed to be however i'm not fixing that in this video i'm just simply replacing the broken capacitor if you're looking for a cheap and easy fix to get by this has worked for me twice now to complete the project all you'll need is a phillips head screwdriver a soldering iron with very basic beginning soldering experience and a 470 uf 16 volt capacitor let's get going so you're going to start by taking the mesh face plate off of the soundbar and it just pulls apart be careful because your wireless remote sensor is in the faceplate so you just have to unplug that and once you get it pried open it just pulls apart you just pull the connection off of the wire and here you go these are the screws that um you're going to be taking apart basically you're unscrewing the speaker housing you're not really taking the speakers out of their housing you're just taking these housings out of the sound bar itself out of the frame and it's kind of denoted by the little arrows on the on the housing so you can kind of see which ones you have to do and um i think all the screws are the same size from what i what i remember but um yeah just go through unscrew everything you have to take all these speakers out in order to get to the components underneath and [Music] um yeah rather kind of a tedious project but not difficult at all here you see you're taking out the speaker housing so that's all the speaker housings taken out and then this is your circuit board with the broken capacitor so you're going to unscrew those four screws and then this is what your your board looks like [Music] so we're looking for that capacitor right in the middle of your screen right there and it's c21 and how you can tell usually a bad capacitor is that it's kind of bulbous or exploded compared to the other ones it's it looks like it's expanded and that's how you can tell it's kind of been fried or shorted so this is the bad one and it wasn't that significant on mine i actually had to use a volt meter to figure out where the power wasn't getting through anymore but that's the one that continues to fry on mine that is fried twice now and so when you flip it over you'll see where you have to solder and where the capacitor is soldered to the board and it's those two little spots right there [Music] so basically you just want to take your soldering iron and heat up those soldering spots and then i pull and wiggle and maybe you just do a quarter out of at a time before the solder kind of solidifies but just keep working it back and forth and you'll be able to pull it out and there it is that's the broken one i ordered this off amazon it was like 10 bucks for a huge variety pack and um this is where we're gonna throw in that's a 470 uf 16 volt capacitor and that's what replaces the one that was in the original sound bar so i just replaced it i know it keeps tripping and you might want to try a bigger one but i didn't i just wanted to replace it so you stick it through you solder it back to the board just a little dab that's really all the solder you need and i suck at soldering as you guys will see especially doing it twice on the same board it looks like crap but it's functional so there we go and then i'm just clipping those long ends that stick through and that is literally it it's all done and this is what it looks like after i've done it twice now it's not pretty but like i said it sure works [Music] i believe that this my aftermarket capacitors were a little bit more narrow the um the ratings were exactly the same between the two but it's a little bit narrower than the one that was originally in it and now i'm basically just putting it back together so i'm screwing back on the uh ac plug and then screwing the board back and then at this point even though everything's exposed i like to give it a test just to make sure everything's working obviously keep your fingers away from anything don't touch anything on the inside you don't want to risk getting shocked there we go see it's working [Music] so yeah so now it's basically just putting everything back together and it's fitting these speaker housings back in and they go in pretty good the cord can kind of get um a little i don't know i guess in the way or it's bent a certain way so just figure out how it's been sitting there for years and then it'll kind of fall back into place and then it's just simply screwing the housings back on to the sound bar themselves i like to alternate my screws that way i just make sure that they all line up and they all get in there and i always forget to do this too when you're putting your mesh faceplate back make sure you plug in your remote sensor i think the very first time i forgot to do that so just make sure you reconnect your remote sensor and then we're going to give it one more final test here make sure that everything's working properly [Music] [Applause] the remote still works volume up and down is fine i check to make sure all the different speakers are working everything's reconnected the way it's supposed to be [Music] so yeah that's it it's very simple it's a pain in the butt but it's not difficult to do um really probably just takes about an hour of time and it's better than buying a new one like i said it's not a permanent fix i've had it go out on me twice by doing this obviously there's a bigger issue going on with a power supply but hey with these tough times and it's hard to get electronics right now and everything else you might want to think about fixing your old equipment before just running out and buying the new stuff so hope this was helpful we'll see you soon [Music]
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