What's wrong with computer speaker?

Wires, alwayx wires.

The indirect speaker is just a "passive" box with a speaker.

Maybe speaker's winding is broken (still wire ! )

The speaker shows 4 ohms. The LED on the (plastic) cabinet goes on, powered by the other speaker. The only other wires are the traces on the circuit board and 2" wires that never move from the pcb to the speaker.

But if it's not possible for the capacitor to be causing this problem, I'll look at the pcb and short wires too.

It's not my imagination, is it, that all the sound goes through the

1000uF cap?

The speakers were upstairs when I took the computer to the basement to repair it, and they weren't used for a couple years.

Is this problem too easy for you guys? I know I'm not up to the level of most of you, but I'd appreciate some help?

I have a pair of computer speakers and the left? one, the one not directly connected to the computer, makes no sound.

The wire must be good because its LED goes on. I finally got it apart (it was glued together) and it has very few parts. The speaker measures 4 ohms and all that leaves is the wires, the tiny pcb, the LED and one 1000uF 16v cap. It seems that all the sound goes through that, is that right? So it could be the problem that it's open.

How come a cap is needed? To protect the sound card? 4 ohms is not enough to protect it? Speakers can short?

I replaced the good speaker with old NIB Jensens at least as big, but I think the sound is worse with stereo speakers than it was with one speaker. Maybe I'm imagining it, but if I fix the 2nd speaker I can find out if I am or not. The old ones are Harmon Kardon and the speaker is only 2 or 2 1/4" but the magnet is really heavy.

Thanks

Some amplifiers have the output that must be above the DC ground so the capaciotr is used to pass the audio but block the DC.

That is for the output there will sometims be two transistors sort of in series between the plus and minus of the power supply. If you short or have a low value of resistance such as the speaker from that point to either the supply voltage or the ground it will blow the transistor, so the capacitor is used.

You could have a bad capacitor, wires, or the amplifier is bad.

Correct, the sound goes through the capacitor. It seems the amplifier sends a DC voltage to light up the led together with the audio signal. So if the led shines the wire is fine and the sound may be lost.in the capacitor. Ma ke sure you are sending an audio signal into the silent channel.

Great. I'll replace it. Easy enough.

16volts 1000uF, I suppose the bag of caps in the basement for the last 30 years are too old to use???? If so I'll buy a new one.

The sound card has both channels because I changed speakers and sound comes out of both now.

That still leaves the possibility that something about the first-pair speaker that works broke and it didn't pass the sound on to the other one. They use different channels of the same amplifier.

But it was hard** to open the speaker, so I'll do the cap first.

**A friend wanted just one speaker, to put in his kitchen, with a wire through the wall from the next room -- Yes, I suggested wireless speakers but he wasn't interested -- I don't know if the stereo issue has occurred to him, but he insisted one speaker***. So I'm giving him the one that works, and if I fix the other one, I'll offer it to him too. Back to opening the speaker: took out the two screws in the back, scraped off the label in back but couldn't find another. Tried to take off the speaker grill but it wouldn't come. A couple days later, tried harder and broke two of the 4 plastic pegs that held it in. Then I see that those two were glued in. Maybe it was falling off, or maybe they're glued in at the factory. So I really don't want to mess with the speaker that's still working, esp. since he wants only one. ***So whether he knows he needs it or not, I've been looking for software that will play a webstream and convert stereo to monaural. I found one or two, so to test, I dl'd an MP3 of a train going from left to right and back again. Sadly, on my system even in stereo it doesn't sound like stereo. I have to work on that!

Thanks, both of you.

Somewhat interesting stories here, including one guy who had never soldered anything, but replaced 2 caps and made his tv work. He had to buy a soldering iron. He watched videos first.

If you have a suitable (15VDC, but 10V or 24V would work, too) power source, clip it onto a few old capacitors overnight. The next morning, unclip 'em, wait a few seconds, and any that make your voltmeter jump, are good to use.

Even if an old electrolytic doesn't meet its original specs after storage, it DOES heal if you give it a voltage bias. I've done it in minutes with overvoltage and a heat gun, but overnight at room temperature is good enough. The capacitor needs applied voltage and time to re-form its oxide layer.

The adapter for my laptop is 17v or thereabouts. I presume the negative side goes to the negative on the capacitor?

All very good, thank you. a) one cap is expensive by mail, plus the postage. (Time is not much of a factor anymore. Mail order is a lot faster than 50 years ago.) b) There was no point to saving these capacitors if I can't use them anymore. c) There is only one store in Baltimore that woudl have this and they fairly far away and expensive. Hmm. Radio Shack is still in business, sort of. (They used to have the best webpage, that said everything a specific store had and how many of them. When I bought one, the number on the web went down.) Well they sell the part but I've waited 10 minutes and "Find in Store" never loads.

But I'll start with what I already have.

I had two never-used caps of the right size in the basement and I was too impatient to try to test them, so I just used one to replace the original.

It didn't work.

Finally someone suggested what I already knew and forgot, to test the speaker with a battery. It clicked the first time the battery was touched to the plug but not again. Then clicked again when the plug tip and ring were shorted to each other. So the speaker was good and probably always good. I should have done this first.

And that means the left channel of the amplifier probably has a problem.

That appears to be the case.

The grill along with its grill cloth was glued in place in the first speaker, and I had to break two of the four plastic prongs to take it off, which was needed to find the screws and take off the back. I suspect the other one is glued too and don't want to break it open, especially since it's going to a friend who only, for some reason, wants one speaker. At least for now. So what good would it do to fix it. I'll keep the second speaker, which has an RCA plug on it.

Thanks for the help.