Powered Computer Speakers - No Sound

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I have a pair of Powered Computer Speakers JBL brand. They worked fine, and suddenly there is no sound. I did not blow them by too high volume, in fact they were shut off, and when I turned them on, they did not work. (I normally have them shut off, since I dont like a "noisy computer". I only turn them on to play MP3 songs, or to watch a video.
They are powered from a wall transformer, which apparently is working because when I push the "ON" button, the light lights up, and I hear a slight click in the speakers.
But they dont play the sound coming from the computer. (Yes, they are in the correct plug on the computer). Thinking there was a problem with the computer audio, I plugged these speakers into another computer (which I know has working audio). Still no sound. I also know that normally, touching the tip of the cord (speaker input wire that goes to the computer), that a hum is heard. Now, there is no hum.
I'm assuming that there is an amplifier board inside the speakers, and it must have somehow died. I have not yet attempted to open them. It looks like there is a screw on the bottom, hidden behind the stand. Whether that will open it, is questionable.
I suppose I should just buy new speakers, but these were good sounding and quite expensive, so I'd like to see if they can be fixed. Have any of you ever repaired these things? Is there an actual amplifier board, or is it just a chip? I have my doubts about finding any replacement parts, unless it's just a capacitor or power supply diode. Or, might there be a fuse???
Thanks
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On Wed, 28 Oct 2015 13:25:22 -0600, snipped-for-privacy@none.com wrote:

Don't assume. What OS do you have?
Do you have a front sound out jack. Plug the speakers into that instead. Does it work now?
Do you have a pair of headphones with the right jack or an adapter so they will fit. Plug them in. Do they work?
What OS do you have?

It seems more likely to me that the wire inside the cord has broken than that the amplifier died.
What OS do you have?

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wrote:

headphones. If not make suere speakers are not muted. Sometimes removing and replacing the audio drivers is required. IF you have sound in the headphones it is a speaker problem. Many GOOD speakers have detachable audio cables - the cable could be bad (or plugged into the wrong jack on the speaker - or even the computer)
An alternative way to test is to plug the speakers into the headphone jack of any portable audio source - like an MP# player.
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snipped-for-privacy@none.com wrote in news:n0723b9ootlunlfmtck3k8088oag54ip2n@ 4ax.com:

try and lower the bit rate in audio properties.
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Try getting/buying an entirely different spkr system.
JBL is now jes Chinese junk, so no big loss. I think I got my current pwrd spkrs (Sony Vaio) from a used computer shop, free, and I have another system, complete w/ a sub-woofer, rotting in the shed. Ppl are throwing them away. If you pay more than $15, even new, yer getting screwed. ;)
nb
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I think you're right. I actually have some small non-powered speakers with a sub woofer and all of that. (made for a home entertainment center). I think I'll look online for a small amplifier, and just use those. At least those speakers are in real boxes that can be opened.
I paid $10 for these JBL ones about 5 years ago, at a garage sale. They were nice while they lasted.
Ideally, I'd run the sound thru an actual stereo system with BIG speakers. I used to do that, but I dont have the room for that in my bedroom, which is where I have my computer now.
Even though these JBLs had decent sound, they were nothing like a REAL Stereo.
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You can usually tell if system is working by fumbling with connector in hand. Should get hum touching tip or ring.
Greg
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snipped-for-privacy@snyder.on.ca posted for all of us...

Haha +1
--
Tekkie

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On Wednesday, October 28, 2015 at 2:26:55 PM UTC-4, snipped-for-privacy@none.com wrote:

Before I looked any further, I'd try one more test. Plug a pair of headphones into the jack where you normally plug the speakers and ensure that you have sound at the jack.
I know you mentioned "another computer which you know has working audio" but I'd stick with the system you are using and be 100% sure it's not the system itself. A different computer adds a another variable. There's no need for that - yet. First eliminate the original system as the root cause.
Do you have an audio extension cord between the computer and the speakers? I do and I once found that it had gotten disconnected behind the desk. I discovered this *after* I determined that the computer was fine by using a pair of headphones.
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On Wed, 28 Oct 2015 11:50:33 -0700 (PDT), DerbyDad03

There is no extension, and it was plugged directly into computer. While the cord could have a break, it's highly doubtful since the wire has not been moved around, it's just been plugged into the computer and not disturbed. I dont own any headphones. I never could stand them. I do have a pair of battery powered mini speakers somewhere around here (for a laptop). When I find them, I'll try them. Either way, if you read the part where I sand there is no hum when I touch the tip of the plug, that alone says the speakers are dead.
I can now see that these speakers cant be opened without destroying them. I took out that screw behind the stand, and the 2 halves of the plastic case wont separate. I drove a screwdriver into the crack and it will not pry apart. It appears that there may be more screws under the cloth over the front of the case, and that cloth is not removable. So either I start making holes in the cloth or just toss them, and buy new speakers. Just more disposible crap that can not be repaired.....
I think it's time to go shopping!!!
By the way, they look like this. http://eclecticreseller.com/index.php?main_page=popup_image&pID !70&zenidf50d263383378186cf4757b266ca5da
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On 10/28/2015 03:39 PM, snipped-for-privacy@none.com wrote:

If there is no hum then indeed they are dead and not worth fooling with any more except for one thing:
This is very rare but I've seen it twice now... the power brick has failed but not completely. Enough power to turn on a light but the voltage drops under load.
Possible that's what happened but not likely
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Everybody everybody!!
Orig. Poster: Quickly the speakers into your smartphone or music player and plays something through it! Sheez!
If you actually hear music through those speakers, then your computer/OS is suspect.
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You rock.
Greg
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On 10/28/2015 4:39 PM, snipped-for-privacy@none.com wrote:

grill will reveal some screws ... if indeed there are no other screws. I once heard of an old film camera that had no screws. But, if you turned the film wind know, which had a small hole in it, to a particular spot, and looked into the hole, there was a screw behind the knob. That screw opened the camera body.
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wrote:

I got it apart. The whole grill comes off. The cloth is attached to a plastic frame and it all pops off. Under there are 4 screws, (plus that obvious rear screw on the back). 5 screws total and it came apart.
As far as testing it. The wall module is marked 12VDC. It measures 15.5 volts, with or without the power switch turned on. That's pretty normal, since a car's battery voltage is about the same. (I'm using an analog VOM meter).
Placing the black lead on a known ground, I am seeing a voltage at random places on the circuit board, such as resistor leads. There are two IC chips on the board, one smaller one (Preamp), one larger one with a heat sink, (Audio Output). The heat sink gets warm if the power is left turned on for awhile. Of course I have no schematic so I cant actually do any actual testing, and ICs are generally near impossible to find replacements for.
Other tests: The input cord has a resistance on both L & R channels to the tip of the cord (with my meter on 1K ohm scale). So that tells me the cord is ok. The actual speaker inside of the case clicks when I touch my test leads to the terminals (with circuit board wires unplugged from it). That indicates the actual speaker is ok.
There are no visual bad parts such as a charred part(s) or bulging capacitors, and from what I can see on that tiny board, there are no loose solder joints or cracks in the board.
This pretty much tells me that the amplifier circuit (board) is bad. Probably one of the chips failed. I'm not sure why the output chip heat sink is getting warm with no sound coming out of it. That may be the failed part, or maybe the preamp chip????? Either way, I now know it's the board itself, and without a schematic and all sorts of testing devices, it's not really possible to test any further. (Nor worth my time).
I'll have to go on craigslist and find some new speakers.
I'm going to save the actual speakers from these. They may come in handy for some other use.
It's kind of weird how this speaker was working fine the last time I used it. I turned it off, and when I turned it on, it was dead. Nothing was disturbed. But I suppose some part died, either a IC chip or capacitor (most likely).
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On Thu, 29 Oct 2015 15:22:21 -0600, snipped-for-privacy@none.com wrote:

are generally pretty generic and not too hard to find, but if it's more than the chip you've wasted the time and money on the chip. And remember - JBL - Junky But Loud ( what all the local audio engineers call them)
What is the number on the chip? Likely something like an LM4732 or a tda2822
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On Thu, 29 Oct 2015 18:11:13 -0400, snipped-for-privacy@snyder.on.ca wrote:

I sort of thought about a power surge......
The output chip is under the tin heat sink, and that is soldered to the board. So I cant read the numbers. The preamp chip looks like it's BA455B. I.m old, so my eyes are not that good anymore. That alone would make it hard to remove and solder in a new chip. On top of that, Ebay has many speakers of a similar type for $10 or less, with free shipping.*NEW* (Buy it Now). Or for around $20 I can get a pair with a subwoofer added. By the time I get the chip(s), I'd probably pay that much, and there is no guarantee it would work. So, I'm just going to salvage the speakers themselves and toss the rest of it. (I'll save the 12vdc wall transformer too). No sense wasting anymore time on these when I can get new ones for around $10. I hate tossing stuff that can be fixed, but this is not worth my time or the money.
I looked on Craigslist too, but nothing was nearby. No sense burning $20 or more for gas to drive many miles either.
At least I now know that it's the board itself that's shot, and there is no sense messing with it anymore.
I should mention that these speakers always were staticy. When there was no music playing, I always heard some static noise and even some popping sound, which got annoying at times. Kind of makes me think a part was failing. I'd suspect a bad capacitor more than anything, knowing the problems caused by caps these days. And when it died, it killed both channels too.
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On Thu, 29 Oct 2015 18:05:00 -0600, snipped-for-privacy@none.com wrote:

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On Thu, 29 Oct 2015 21:42:13 -0400, snipped-for-privacy@snyder.on.ca wrote:

So what brand is halfway decent? I know something like Bose is top pf the line, but I'm not spending $100 to $250. I see a lot of Insignia, Logitec, and Vibe on Ebay. I dont want another JBL considering how it fried.
By the way, I found those non-powered mini speakers for my laptop. They proved that my computer has sound. Pretty lousy sound from those speakers though, but it beats no sound, till I buy something new.
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