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A general-purpose audio device that transmits low audio frequencies to your ears.

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Subwoofer bad power suppply or amp?

First of all, good day to you! and please can you give me a hand?. Join my journy with this subwoofer Klipsch R112SW:

Right after the warranty ended this subwoofer started to fail, first it started making a noise when turned ON, like a grounding or false contact for a few seconds and then it was silent and working fine but at random moments started to do the same sometimes i had to turn it off because it started to do it loud (always jumping from quiet to loud at random, the noise not the audio, i found it on youtube with the word "rattling sound" but no pops or anything else) after a few weeks this got worse and one day after turning on the Sub it went Off seconds later, the only way to turn it back ON was disconnecting the power cord and plug it in again.

I took the subwoofer to fix on the same place i bought it, they fixed and told me it was the power supply and 8 months later (since last week) im having similar issues but not that bad, this time it does this noise when i turn it ON after being Off a few hours and just for a few seconds and never again.

Since they told me it was the power supply and the place is 2hs away from my home (the fix was expensive too)... i decided to open the %#*@ thing myself and check for a bad capacitor or something since i know how to replace components and since is doing something similar from last time (before the fix) i figure the solution could be the same, well i took a look at the board and i couldn't find anything looking bad (only yellow stuff I believe is glue that came from factory and some brown stuff from the same thing, the heat turned the yellow to brown?), so i decided check on the back of the board soldering marks and replace some of the same components to test and also clean the pcb from the flux they have used.

Looking the components i saw only two capacitors that looked like discolored (from heat maybe?) and decided to replace this two only to test, results:

Both 22uf 50v were replaced with 22uf 63v

Then powered the Sub and voila! the quiet to loud random noise stopped but still does some low noise went i turn it ON from a few hours of having the Sub unplugged (check the video):

Now the sound level remains low and last just a few seconds (10-20) and remain on the same sound level, it doesn't go from quiet to very loud at random so i assume im on the right track. After this wall of text (sorry) can you give a hand and tell me which component could be causing this or if i could fix it myself just replacing capacitors? if yes is ok to use capacitor with a little higher V but same uF? Is hard to get the exact same.

Here some pics.

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@falita without having a proper schematic etc. but by looking at the board, I’d replace the 3 caps and 1 resistor for sure. This could just be normal for this board but it sure looks like some electrolytic residue from a bad cap. Once you replaced those, reevaluate. Yes, it is okay to go with higher values, just never lower.

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Yeah, im still searching the schematic to have an idea of what im touching but im considering of changing all the caps, i wasn't sure about changing them all because is getting really hard to get the same V and the ones i can get are a little bigger and after a few im gonna have trouble with the space and they all will be touching each other. The brown stuff seems to be the yellow glue but burnt, i found this pic on the 15' model:

Link to the site:

And the picture of the same spot:


Yes absolutely possible but again that does then look like it is getting way to hot. I'd go ahead and change those parts and also check the pots to much sure that those are okay.


Update: replaced all capacitors and resistors, the first time i turn it ON i heard the rumbling veeery quiet for 10 seconds and then went way, is kinda of a success. No idea what else to try or if this is my new normal behaviour. Been running fine for 2hs now and maybe the quality of the bass improved? must be placebo or the days of not using the unit


@falita this may just be normal behaviour until everything is powered up etc. For now, enjoy it and see what the future holds. Good job getting it fixed.


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