Bad caps or inductors on Klipsch ipod speaker unit

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Ok, so what i did may not be 100% valid but i think it may prove my point. Recall that i removed two caps.........one was worse than the other. The worse one was in the same position as CapA. The other had a measured cap value of ~ 420uF (should be 470uF). I put the 420uF back onto the board in place of capA. The goal here is that the original ones should have ripple and ESR values that are good.........provided the caps are good. I think the 420uF cap is good enough for this test.......but there is a possibility that its not.

I put the 420uF original cap back in............still got hot. As best i can tell at the same rate as the other one.

So i dont think the actual cap is the problem. I think its something else.

Willing to take comments on this.

Also, willing to take suggestions on what to try next.........not sure what to measure. I have measured the voltage across caps when power is turned on......its 15V..........once song starts playing voltage drops to 8V and starts to heat up slowly. Almost not noticible at first.

Could the power cord be somehow causing the problem? I dont know. Suggeestion would be great. Otherwise to the trash this thing goes.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

is it actually playing music while it's getting hot?
i'm wondering if the coil may be shorted in one of the speakers dumping the load back into the cap.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

When i say playing music i should have clarified a bit. I actually have the speakers disconnected because with them connected i really cant probe around the board looking at voltages. So when i say playing music what i mean is that the ipod is playing music through the unit........just the speakers are not connected. With the ipod attached to the unit but not "playing musics" the capA does not heat up.

I was wondering if once the ipod started playing music that it was at this point in time when an actual "load" was being put on the "power cord" .........but i dont kinow.

At a loss really.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I am enclosing a picture of the power cord since i keep referring to it.

How to test is the power cord is operating correctly? If i am looking in the wrong place just let me know..........but if you know how to test such a thing please let me know.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

that's a switching psu, you'd need a scope to check that.

[Radio Fox]

Re: Bad caps or inductors on Klipsch ipod speaker unit

When i say playing music i should have clarified a bit. I actually have the speakers disconnected because with them connected i really cant probe around the board looking at voltages. So when i say playing music what i mean is that the ipod is playing music through the unit........just the speakers are not connected...

I dont know much about class D amplifiers, but I would never run any kind of audio amplifier with the speakers disconnected. You could damage the output IC/transistors. Is it possible to extend the speaker wires so that you can connect them & still access the board?

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

wow..........did not know that. Its just that with the speakers connected there is almost "0" chance of me probing around with a voltmeter.

[Radio Fox]

Re: Bad caps or inductors on Klipsch ipod speaker unit

wow..........did not know that. Its just that with the speakers connected there is almost "0" chance of me probing around with a voltmeter.

Is it possible to reconnect the speakers just to see if the capacitor still gets hot after playing music for a few minutes?

Can I assume that since changing the 2 capacitors, you haven't actually reconnected the speakers to see if the original symptoms still exist?

As I said in my other post, if you wanted to take voltage readings with the speakers connected, you could unsolder the wires from the speakers, & extend them by temporarily adding your own length of wire.

[seanc]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I am enclosing a picture of the power cord since i keep referring to it.

How to test is the power cord is operating correctly? If i am looking in the wrong place just let me know..........but if you know how to test such a thing please let me know.

When I'm really suspicious of a faulty power brick, or it's just not working, I take a hacksaw to it to break the seams and and crack it open with a screwdriver. The end result isn't pretty, but as long as it works I'm personally not bothered.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

you freeze it in a bag,
then put it in a vice and tighten slowly.
that will usualy crack the glued seam without damage.

[seanc]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Now that's a good idea, thanks

Up until now the stuff I've fixed was destined for the bin anyway, so I just wanted to open them to see what was inside.

The repaired power bricks that I've kept are just hidden away in power strips under desks... apart from the one I can see in the wall wrapped in yellow electrical tape :P

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I dont know if this will work but i wanted to ask anyway.

I have read somewhere online (does not make it true) about wiring up an automotive bulb/lamp and putting one lead on the +V and one lead to the gnd of the power cord...........But what i am not sure of is what i am supposed to see after i do this. Also, if 15V are coming off the power cord do i need at least a bulb that is 15V or higher (i only have a 12V right now).

Any thoughts on this?

Am i wasting my time thinking it could be the power brick?

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Also, radio-fox.

I would wire up the speakers but there are "4" wires going to the speakers not just two. So let me do a bit of investing on this one. THanks for the input.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

forget the car bulb - that's just to test if you dont want to risk your stuff.
you already tested & found 15v - test-complete.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Its been a while since i posted on this particular thread but i recently bought two 470uF low ESR value caps to put into this thing to see if this fixed the problem.

Well, it did not. I "THINK" it may have helped a little........ie....takes a little longer to get hot now but it still gets hot. I did a little probing with my finger and i found something i wanted to ask about.

I am enclosing a pic as reference. Note: The two new caps i put on the board do not happen to be in the pic.

In the pic i identify 3 surface mount small caps. CapA gets hot...very hot. Caps B and C also get hot but not as fast or as hot as cap A. Could this capA be the problem or do you think its something else?

[PlainBill]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I dont know if this will work but i wanted to ask anyway.

I have read somewhere online (does not make it true) about wiring up an automotive bulb/lamp and putting one lead on the +V and one lead to the gnd of the power cord...........But what i am not sure of is what i am supposed to see after i do this. Also, if 15V are coming off the power cord do i need at least a bulb that is 15V or higher (i only have a 12V right now).

Any thoughts on this?

Am i wasting my time thinking it could be the power brick?

That's an excellent idea. The brake filament on an 1157 bulb ?(commonly used in many automobiles) is rated for 2.1 amps at 12.8 volts. Hook it up to the power supply and measure the output voltage. If the voltage drops down to about 8 volts it would be a good idea to open the power brick.

PlainBill

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

ok.....

What about the "caps" in the picture? Do you think they could be bad? I had heard that these caps rarely go bad.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Do you think if i replace the small caps that thiswill eliminate the heating?

Anyone got a suggestion?

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Its been while since i posted anything here.

But i wanted to let you all know that thanks to bad-caps forum i was able to figure out what the "problem" is......ie...what is causing caps to get hot.

It was the EXTERNAL power supply. I did the lamp test and it was obvious that the bad supply made the lamp burn brighter than the good supply.

I also verified that using a good supply the cap does NOT get hot.

I am attaching a pic of the lamp test using a good and bad supply. Its hard to tell from the pic between good and bad but look at the amount of light output for each.....the bad supply has a larger diameter light output as compared to the good supply.

The pics are not as good as i had hoped......if your just looking at thelamp its easy to see the bad supply is much much much brighter......so bright it hurst your eyes.


Now comes the task of figuring out what is causing the external supply to output more current than its supposed to.

Note: I did measure "voltage" of the bad supply with nothing connected to it and it was as it should be ~15V. This is the voltage value on the label of the supply.

[PlainBill]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Its been while since i posted anything here.

But i wanted to let you all know that thanks to bad-caps forum i was able to figure out what the "problem" is......ie...what is causing caps to get hot.

It was the EXTERNAL power supply. I did the lamp test and it was obvious that the bad supply made the lamp burn brighter than the good supply.

I also verified that using a good supply the cap does NOT get hot.

I am attaching a pic of the lamp test using a good and bad supply. Its hard to tell from the pic between good and bad but look at the amount of light output for each.....the bad supply has a larger diameter light output as compared to the good supply.

The pics are not as good as i had hoped......if your just looking at thelamp its easy to see the bad supply is much much much brighter......so bright it hurst your eyes.


Now comes the task of figuring out what is causing the external supply to output more current than its supposed to.

Note: I did measure "voltage" of the bad supply with nothing connected to it and it was as it should be ~15V. This is the voltage value on the label of the supply.

You've got it backwards. The bad supply isn't putting out too much current, it's output has too much RIPPLE. Odds are the output caps are bloated.

PlainBill