Bad caps or inductors on Klipsch ipod speaker unit

[Welchs101]

Not sure if this is the right place or if there is another location in the forum this should go. But here goes.

I have a Klipsch ipod speaker unit that a friend asked me to look at. It would play for about 5 to 10min and then "shut off". Once it shut off it would not play again for at least an hour.

I opened up the unit (took a LONG time to do that) and i found what i think the problem is. Its either the cap or the inductor (see enclosed pic). There is the "gunk" which looked like it ozzed from either the cap or the inductor.

Any ideas from the pic which its from?

Also, the caps are "surface mount" caps ..........how to remove the caps to measure?

The inductors are the black looking things with the "150" on top. Any idea what inductors are these.......ie...if i wanted to replace them what do i replace them with.

[sofTest]

Re: Bad caps or inductors on Klipsch ipod speaker unit

The brown "gunk" looks like burnt glue, that are used to keep things in place during production. In some places its still yellow. Originally it's not conductive, but burnt like that, it might become conductive, and cause your problem. Clean it away.

Any chance of a picture from the underside of the board?

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Your right. The "gunk" is burned glue.

I am enclosing a pic of front and backside of board.

Also, i have removed two surface mount caps and one through-hold inductor.

Both caps are supposed to be 470uF/25V caps. One of the caps measured 298uF so its bad i know that. The other measured 432uF so its probably bad as well. The inductor measured as a short...0.2ohms.

So what do i know. I know i have two bad caps. BUT what is surprising is if you look at the first pictures i posted you will see "burned" glue around all 4 inductors and around both (two) caps. Could the TWO bad caps have caused burned glue around all those devices. Seems strange to me.......any thoughts anyone?

[PlainBill]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Your right. The "gunk" is burned glue.

I am enclosing a pic of front and backside of board.

Also, i have removed two surface mount caps and one through-hold inductor.

Both caps are supposed to be 470uF/25V caps. One of the caps measured 298uF so its bad i know that. The other measured 432uF so its probably bad as well. The inductor measured as a short...0.2ohms.

So what do i know. I know i have two bad caps. BUT what is surprising is if you look at the first pictures i posted you will see "burned" glue around all 4 inductors and around both (two) caps. Could the TWO bad caps have caused burned glue around all those devices. Seems strange to me.......any thoughts anyone?

The only theory I can come up with is bad capacitors will result in additional ripple through the inductors, causing them to heat up also. Checking the resistance of an inductor will only tell you the winding isn't broken. It won't detect a shorted turn. To do that you need a ring tester.

I have several suggestions for testing it however. Replace both caps; one is clearly bad, the other is marginal. Remove the burnt glue. Reassemble and test it. When it fails quickly open it to see which parts are hot. Try freeze spray on suspect components until you find one which when cooled will allow it to immeadiately begin working.

PlainBill

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Hi,

Since i will have to order from digikey the caps (i dont have any surface mounted caps) i was thinking i should also order the inductors as well. But i dont know what inductors to order.

The inductor has "150" printed on it but thats it. No other information about manufacturer or specs. The inductor does have a metal case like i have never seen before. Kinda cool.

Any advice on what inductor to order?

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Also, any advice on how to remove the "burned on glue". Its really hard to remove.

[sofTest]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I use isopropyl alcohol, and a cotton tipped pin, for cleaning electronics.

I can't help you with the inductor.

As for the cause, it has been told on this forum that old glue has become conductive in some cases. That also might be the cause for it to become burnt. I would have removed all glue touching components, if I were you.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

anyone have any advice on what inductors to order?

[kikkoman]

Re: Bad caps or inductors on Klipsch ipod speaker unit

you don't need to replace the inductors, it's normal when they read a short.
unless the heat has cracked the cores, you can leave the old ones in place.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

The capcitors that are "bad" are surface mount caps..........has anyone every tried to solder on a "through-hole" cap onto a location where a surface mount cap once stood? I am not talking about drilling a hole or anything just placing / soldering cap onto surface.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

i have - regularly.

i put a pcb against the edge of the new cap lead at the base to act as a spacer & bend the lead out at a 90' angle.

then trim them short to fit on the pcb pads.

put some solder on the pads, paint liquid flux on the cap leads & pcb pads,

hold the cap in place and heat each joint from the side so the solder melts and the wire drops onto the pad.

i do this because smt electrolytics are junk - they are too small and have a very short lifespan.
sometimes i even replace them with tantalum's

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Hi STJ, I think i followed most of what you said but i am not sure what you do with the "pcb" board. You use this just to ben the lead? Do you have a pic you can send?

Thanks for the info!

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Based on the previous instructions. I thought i would show a few pics of what was said. This method works really well.

If you have any other advice or if i am doing something wrong please let me know.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

you put some solder on the board,
then put some flux on it so when you melt it again it will stay nice - if you know what i mean.

if you have 3 hands or a friend then you can just use your 3rd hand to hold the cap in place and use your other 2 hands to hold the solder & iron.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

your steel-ruler is a bit thin btw, that's why i use a pcb.

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

I agree. I think using that steel ruler was not the best choice. But could not find a spare piece of pcb.

Thanks for the input!

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

you were working on a pcb!

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

ahhhh very good point. Never thought of using that one.

thanks.

[stj]

Re: Bad caps or inductors on Klipsch ipod speaker unit

[Welchs101]

Re: Bad caps or inductors on Klipsch ipod speaker unit

Well, i replaced the capacitors. I turned the unit on and waited about 5min. Remembering what Plain-Bill said i reached in and physically touched the cap and inductors. They were HOT! Too hot to keep my finger on for even 1sec.

So i think there is something else wrong. I had hoped changing the two caps would solve the problem but it did not.

4 of the inductors and 2 of the capacitors are "HOT". NOt sure why. Nothing visually obvious that is bad. Anyone have any ideas on what to check next?