Have an old Klipsch 4.1 speaker system? Did it die? I bet you can fix it!

Updated with Crappy Photo Guide Tour


I thought I would post about something I fixed last week.

So, while I was at work, my wife needed a power outlet, so she unplugged my Klipsch 4.1 speakers from the surge protector (not the V2.400 version, but the newer revision that Klipsch made right after that. all this is applicable to both though, as all klipsch really changed was the crossover points for the satellites).

Long story short- wasn't muted, so when she plugged it back it- speakers no worky no more.

These aren't the best speakers, but for casual computer music and gaming use, they're great (and I've had them for a pretty long time).

So I opened up the subwoofer (to get to the amp) and saw that there were two resistors that had some problems:

R12 and R26. (680ohm and 47k ohm, respectively).

Note: these first two photos are not my photos- I found them elsewhere. (My Photos are now added at the end of the post, below) They give you a good idea of what has happened though. The R12 picture shows the zip tie. My zip tie was completely melted, and broken through! But, the R12 was still working. My R26 was way worse than shown in the second picture though...


R12 is the gray resistor.

R12 heated up like a bitch in heat, and melted a zip tie that was used on the board for structural support. But, after measuring the resistance with my DMM, 680ohm on the button- so this wasn't the problem. Sure was scorched though...


R26 is the brown resistor.

R26 basically exploded. The shell of the resistor was cracked, fragmented, and the current path was completely blown open.

Well, using my trusty soldering iron, solder, some desoldering braid, and some new resistors from Digikey, I replaced R26.

My speakers work again!!!

Here is a link to some rough schematics that some guy made, if you are interested:

http://www.thompdale.com/bash_amplifier/bash_amp.htm

By the way, I think the original R26 was a 1W resistor, so I replaced it with a 3W lol. I also bought some replacement resistors for R12, just in case it decides to go later.

I hope this helps someone out there. (these two resistors seem to be a common problem with this particular amplifier)


Crappy Photo Guide Tour:


Photo 1: Unopened subwoofer box. The screws you need to remove are circled in red.





Photo 2: Subwoofer box open. Careful now, don't rip it open so fast. Look underneath the board, and disconnect the speaker leads from the board.





Photo 3: Insides of the subwoofer enclosure, with the amp no longer in place.





Photo 4: Entire plate amp assembly.





Photo 5: The new R26 I put in place (47k ohm). Notice its large, manly size. That's because it has a 3W power handling capacity. The old one only had a 1W capacity. Arrows indicate where I had to bend the resistor leads to fit it in the PCB holes





Photo 6: Rear side of the PCB (the side you solder on). Yeah, I used a tad too much solder. no harm done.





Photo 7: Old, destroyed R26 (47k ohm, 1W).





Photo 8: Old R12 (680 ohm) still going strong. Notice the charred PCB? Excessive heat melted the zip-tie that was connected to the board at the red circled hole. The black stuff is from the burning of that plastic zip-tie.





Photo 9: Old fuse, still intact. If only this were the common failure point! lol fucking klipsch....





Photo 10: One of the rows of MOSFETS. Mine are fine, but I think I once read about someone having problems with those, and them fixing it.





Photo 11: The other row of MOSFETS.

IIRC, one of the issues with ProMedia power supplies crapping out is under-rated resistors like this in the amp in some sort of Class A circuit. I was pretty sure that the amplifier design as Class B (push-pull) but I distinctly remember someone stating that these parts overheat regardless of power consumption and, in actual fact, fail less often when in use because the movement of the sub circulates air in the sub chassis. Instances of failures were higher for ProMedia systems left on but playing no audio. Go figure.

Thanks for posting specifics. It seems that most people who learn specific components and values decide to start an online ProMedia repair business instead of sharing with the community.

Hey man- no problem. I just want to save some people out there some money!

Yeah, the resistors definitely didn't have enough power handling. I replaced them with 3W versions, and if they ever blow, I guess I'll go to 5W, since the leads will still be the same diameter, and I will still be able to solder them to the board lol.

oh, and by the way, to the people with dead speakers:

by "dead," I mean the LED near the "mute" button doesn't turn on, and you have no sound- nothing. This might work for other failure symptoms too- so you might as well unplug the sub, open it up, and check the values of those resistors anyway!

Representative pics added in first post.

update -

the results speak for themselves.

After solid use of the speaker system over the past week, including a lot of music and gaming, it sounds as good as it did when it was brand new.

Hey guys!

Boy, I am glad to have found this thread (and the other related ones in this forum). I have the promedia 2.1's and have been having problems with them for probably almost a year now (I've owned them for 4+ years).

My problem is the subwoofer barely ever works anymore. Initially, it started off with the subwoofer not working for a minute when I first turned the speakers on, but after it "warmed up," it would work. Then, it took longer and longer to "warm up." Now it rarely works, if ever. My satellites work fine and always have, my control pod is fine, and my DIN plug is fine. This leads me to believe it's an internal amplifier or transformer problem, but I'm not an electrician (I took an ECE class back in school, but that's about it; I'm an ME by trade.) and I have really no idea what's going on inside.

I took the amplifier out and looked at everything, but I didn't see any obviously burnt resistors or capacitors or the like. I did take a bunch of pictures, and I am going to post them here, along with the request that if anyone has any ideas or sees anything funny in the pics, please let me know. I do have access to a soldering iron and my technical aptitude is decent, so any suggestions are appreciated. I'm just wondering if it has somethign to do with all that green goop that looks like it melted all over the place.

The pictures start out from the bottom of the amp (when I refer to bottom, I mean the vertical bottom, as the amp is mounted vertically in the sub enclosure). You can see where the A/C input is, as well as the fuse in the first pics. The second pic (3008) would be looking "uphill."

Thanks a bunch,
-Dirk

from the same guy's page I linked to for the 4.1 systems, here are the 2.1 system schematics:

http://www.thompdale.com/bash_amplif...1_bash_amp.htm

I'm not sure what the problem is. The symptom you describe seems to be something I've heard about happening before, but I don't know what it is (I'm a CE (SE) by trade lol - not a EE. I just know enough about electronics to be dangerous)

I recommend you post on an audio forum, specifically one dealing with home audio amplifiers, or the like. (electronic components working only after "warming up" can be indicative of a loose connection, or something else. and the "something else" is probably a well-known thing that amp guys would know)

you could also start by verifying your fuse is okay, as well as some of the bigger resistors. You just need a multimeter. I'm assuming the fuse is fine....

I'll do some reading and see if I can come up with anything.

edit: oh, and something to add. I bought the 4.1 system a while back, when Klipsch was just getting into the "multimedia" side of things.

Klipsch should have stuck with what they have always done best - loudspeakers. They suck at building amplifiers lol

You are tempting me to grab some "broken" 4.1 Promedia's! Do you think it is just a simple resistor issue everytime or were you just lucky?

Somewhat OT: Why did Klipsch stop making surround computer speakers?

well, it's definitely a common failure point. I've seen numerous instances in which failed R12 or R26 were the cause of the system failure.

Symptoms include:

Dark LED light - i.e. no power lol

I've also seen cases where a different component failed (like a MOSFET for example)- but it's mainly been those resistors. (at least out of the cases that have been reported on internet forums)

Why did they stop making surround computer speakers? You know, I'm not sure. Oh, wait, yes I am. Klipsch sucks at building amps! lol I guess the failure rate of their surround systems was higher than acceptable, and they didn't want to fuck with it anymore. Their customer service is abysmal.

I speculate that the 2.1 systems have a lower failure rate.

Mine just died two days ago, after 10 years. how do I open up the sub, and it is safe to start removing surface level components from the PCBs once I get it open? I have a multimeter to check for a charge in capacitors (so I don't die).

Originally Posted by sabregen

Mine just died two days ago, after 10 years. how do I open up the sub, and it is safe to start removing surface level components from the PCBs once I get it open? I have a multimeter to check for a charge in capacitors (so I don't die).

First, please unplug the system (of course lol).

I'm assuming your system is a 4.1 model?

There are screws on the back of the subwoofer, securing the plate amp to the wooden enclosure. Unscrew those screws, and you can pull the plate amp out.

Be careful, and do not pull it out very far without first disconnecting the leads from the subwoofer drivers from the PCB. You can simply pull off the connectors. There are 2 connectors to the PCB for the subwoofer drivers.

I wouldn't worry about getting hurt, just follow all the basic safety rules. (i.e. don't put a capacitor in your mouth, etc lol)

My bet is that you have a blown resistor. Check the usual suspects (R12 and R26). Note that just because they looked burned doesn't mean they aren't working.

My R12 is really scarred and burned up, but it still is showing the proper resistance, and still works. My R26 was the problem.

Be sure to check the values with your DMM. Also note that you might not be able to get a proper reading, depending on the oxidation and/or corrosion on the resistor leads. You may have to test the resistance at the lead-to-pad connection on the PCB. Basically what I'm saying, is that you need to be careful measuring the resistance, so you don't get an incorrect reading.

(it's possible to think the resistor is blown when it really isn't, just by not getting good contact to the leads of your DMM)

edit: If it's a blown resistor, and you are going to replace it, replace it with a resistor of the same value (ohms) but of higher power handling capacity (watts). The new one will be bigger, and you might have some trouble fitting it to the board.

If this is what you end up doing, let me know and I'll take some pictures of what I did. In fact, when I get home from work today I'll open up my amp and take some pictures.

Yes, they are:

Klipsch ProMedia v2 4.1's

This is very good news, and thanks for the little write up. If I can get these fixed, I'd much rather do that. I have, over the last 10 years, become very attached to them, and would rather fix them than have to get new ones (although I was planning on it relatively soon, just not now). Thanks again. Hopefully I'll get to looking at this, this weekend. I'll be sure to reports back.

Originally Posted by TOOL1075

from the same guy's page I linked to for the 4.1 systems, here are the 2.1 system schematics:

http://www.thompdale.com/bash_amplif...1_bash_amp.htm

I'm not sure what the problem is. The symptom you describe seems to be something I've heard about happening before, but I don't know what it is (I'm a CE (SE) by trade lol - not a EE. I just know enough about electronics to be dangerous)

I recommend you post on an audio forum, specifically one dealing with home audio amplifiers, or the like. (electronic components working only after "warming up" can be indicative of a loose connection, or something else. and the "something else" is probably a well-known thing that amp guys would know)

you could also start by verifying your fuse is okay, as well as some of the bigger resistors. You just need a multimeter. I'm assuming the fuse is fine....

I'll do some reading and see if I can come up with anything.

edit: oh, and something to add. I bought the 4.1 system a while back, when Klipsch was just getting into the "multimedia" side of things.

Klipsch should have stuck with what they have always done best - loudspeakers. They suck at building amplifiers lol

Thanks for the reply. On the suggestion of posting on audio forum that deals with amplifiers - got any suggestions? I've done a search, but if you know any that are particularly good, I'd love to hear about them. The fuse is definitely fine though; the speakers always power up fine, and the satellites always work ... its just the sub, unfortunately.

Originally Posted by dirkdigles

Thanks for the reply. On the suggestion of posting on audio forum that deals with amplifiers - got any suggestions? I've done a search, but if you know any that are particularly good, I'd love to hear about them. The fuse is definitely fine though; the speakers always power up fine, and the satellites always work ... its just the sub, unfortunately.

This forum would definitely be a good place to ask.

I know I said I'd open up the sub now (I'm home from work) but I'm so lazy... and it's Friday lol...

I gueeess I'll open it and take some pics

stand by...

:-)

I took pics and updated the first post.

Yes, the camera is crappy. And yes, I'm not a photographer

I hope the photos help.

Here's what I found when I opened mine up. the resistor is awfully crispy, the fuse is still good. the large capacitor seems to have leaked some.

yeah, my capacitor is like that too - it's probably okay.

So, is R12 not working? It doesn't look like its blown. You measure it?

What about R26?

edit: oh, yeah, your R26 is done for I think. Replace it, and you're good to go. (but measure it first, just to make sure lol)

I have a multimeter, but I've only ever used it to measure voltages. How do I measure ohms? It has the settings for it, but I don't know how to do it properly.

okay, set it to measure resistance.

R26 is 47k ohm. (47,000 ohms)

So, set your multimeter to measure resistance, and turn it to a resistance ABOVE 47k ohms. Mine has settings for:

200
2k
20k
200k
2M
20M

To measure a 47k ohm resistor, I would turn it to 200k.

If there is infinite resistance (meaning the resistor doesn't work) then the resistor is bad.

Test R12 first. For R12, I would turn my meter dial to "2k" because 680ohms is less than 2k, and greater than 200.

I'm not sure what settings your meter has, but this should help I think.


edit: Your meter will probably read "infinite" or "1" if:

A. The resistor is blown open

B: You aren't getting good contact

C. Your scale is set too low

If I measure a 47k ohm resistor with my DMM, and I have the dial set to "200k," it will read "47."