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

Discussion in 'Computer Audio' started by TOOL1075, Aug 8, 2008.

  1. melteye

    melteye [H]ard|Gawd

    Messages:
    1,853
    Joined:
    Sep 29, 2000
    Thanks. There is indeed a short in the bridge rectifier (KBU606.) :D

    https://dl.dropboxusercontent.com/u/24697861/ProgressSoFar.jpg

    Ordered the replacement varistor and bridge rectifier for the IO board and already replaced the op amp on the control pod. I've spent $8.40 so far and I have 5 extra op amps and 3 extra varistors. Not bad.
     
    Last edited: Nov 26, 2013
  2. Brian48

    Brian48 Limp Gawd

    Messages:
    349
    Joined:
    Jun 23, 2004
    Great thread. My Promedia 4.1 is still working fine. Good to know I can still salvage it if it ever finally dies on me.
     
  3. AeaKOS

    AeaKOS Limp Gawd

    Messages:
    348
    Joined:
    Feb 2, 2001
    Just wanted to post a thanks to the Op. Using your guide, I was able to restore my amp by replacing R26 too. Nice work.
     
  4. helcul

    helcul n00bie

    Messages:
    1
    Joined:
    Dec 5, 2013
    Hi everyone,

    My 4.2-400 started buzzing so I logically found my way to this great thread. I have had this plugged in for 10+ years with lots of use but also lots of sitting around soaking in its heat. Our cat can often be found sitting on top of it enjoying the warm spot.

    So I opened up my subwoofer and found 3 spots of distress. The two 470uF 63V capacitors appear to have leaked and the R12 and R26 resistors show their age (though they tested to the correct resistances).

    I ordered replacement parts (capacitors from Radio Shack and resistors from sourcingmap.com). The caps came first so I replaced them and tried the system again. The system is still buzzing; however, I learned that the buzzing is definitely only on the bass channel. I know this because I forgot to hook up the bass and thought I had fixed the system (since the buzzing went away). When I went to adjust the bass I realized it wasn't hooked up.

    My question is, could the R12 or R26 resistors cause the bass channel to buzz? If I need to probe and isolate components to locate the problem, does bass channel buzzing help indicate where should I start?

    Thanks everyone who has contributed to this thread...this is the internet at its best!

    Sincerely,
    Helcul
     
  5. melteye

    melteye [H]ard|Gawd

    Messages:
    1,853
    Joined:
    Sep 29, 2000
    Recap: The led on my control pod turned off and I lost sound. I replaced OP-AMP and plugged everything in with success. An animal chewed through the power chord that same day causing a short (reset circuit breaker.) After fixing the chord and replacing the fuse the board would keep blowing fuses. I then replaced the transitor and bridge rectifier. It no longer blows fuses but now I'm once again getting no sound and no light on the control pod.

    Edit: I ended up testing every single resistor and transitor on all the boards.

    DC-DC Converter
    =============
    R5 (1k ohms): 131 ohms
    R7 (205k ohms): 150 ohms
    R27 (4.7 ohms): Infinite

    Digital Converter
    ============
    All reads well.

    IO Board
    =======
    R11 (2.5k ohms): 82.6k ohms
    The varistor and bridge rectifier have been replaced.

    Control Pod
    =========
    All reads well.
    The OP AMP has been replaced.

    I have already desoldered the five components... now to order the new ones (should be less than $10 for a bunch of em.)
     
    Last edited: Dec 7, 2013
  6. melteye

    melteye [H]ard|Gawd

    Messages:
    1,853
    Joined:
    Sep 29, 2000
    http://www.thompdale.com/bash_amplifier/4-1/4-1_i-o_board_986x709.gif

    It shows R11 as 2.5k... however the resistor I'm holding in my hand is definitely not a 2.5k resistor. It's grey-red-green-red-purple which is 82.5k ohms 0.1% Which is pretty close to my 82.6k ohms value. Typo on the schematic or just a different version of the IO board?

    I'll be soldering back on.
     
    Last edited: Dec 7, 2013
  7. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    I do believe this to be a typo. Did you check the resistances with the components removed from their board locations?
     
  8. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    This might be the case. Buzzing would indicate "dirty" power going to the amplifier or a problem with the low-pass filter. R26 is a part of the power circuit, but it seems to regulate the amount of current going to the primary of the step-down transformer. I'm not sure what R12 does exactly, but it is a part of the BASH module.

    I would first look at the bridge rectifier, as this seems to be a common failure point, and would definitely give you dirty power with a 60Hz frequency, which could definitely cause a buzz.
     
  9. melteye

    melteye [H]ard|Gawd

    Messages:
    1,853
    Joined:
    Sep 29, 2000
    I did indeed. A few of the 10k ohms resistors I removed ended up reading perfectly outside the board so I was sure to confirm the rest.
     
  10. melteye

    melteye [H]ard|Gawd

    Messages:
    1,853
    Joined:
    Sep 29, 2000
    The parts came in and I just soldered them in. I am getting power and the LED is now lighting up again. Now I'm having an interesting issue.

    1. No matter what sub-level or volume is used there is no sound from the subwoofer, unless I am unplugging a cable or adjusting the sub-level pot (and then I definitely get some sub movement).

    2. If the sub-level is at 0 the speakers will play audio at low volume, when the sub-level is raised it cuts off speaker sound. If I raise the sub-level I can raise the volume (and max sub lets be set the volume to wherever I want.)

    Edit: The capacitor on the digital converter blew and took everything with it. Rest in peace Klipsch Promedia 4.1's.
     
    Last edited: Dec 13, 2013
  11. DreamBeamz

    DreamBeamz n00bie

    Messages:
    3
    Joined:
    Dec 15, 2013
    Stay away from Elliott-tronics AKA Elliott Sanchez. This guy is a total rip off. His paypal account was deactivated and recreated a new account under Jessica Sanchez. This guy has kept my equipment for over 6 months. Lied to me about the timeline, that I would get it soon. Tell me he's waiting on one part, on and on. The parts and my equipment were never returned. STAY AWAY this guy, he is a FRAUD!!! Do your research, he's did this to many people throughout the internet forums and he lives Cedar Hill, TX. I'm about to take a trip to Dallas to go claim my equipment and get a refund with filing legal action through small claims court. HE ignores my emails and I'm going to tell everyone about his POOR service. Go find another engineer or tech on ebay for your Klipsch pro media 5.1 amp repair. If you choose poorly like me, then you will be in the same situation. Research before you send anything to this guy!!! Look at the payment history. [​IMG]
     
  12. Evil Scooter

    Evil Scooter [H]ard|Gawd

    Messages:
    1,691
    Joined:
    Sep 22, 2000
    Just replaced the R12 and R26 resistors with 2Watt models, the old ones were really crispy. The persistent buzzing that had nearly caused me to toss the sub and use the satellite speakers in my garage is now gone and they work great.. thanks! :D
     
  13. ronss

    ronss [H]Lite

    Messages:
    69
    Joined:
    Oct 31, 2006
    i have the klipsch 4.1 pro media speakers...i get on 2 speakers to work, period...the light on the control speaker is working....i have plugged my speaker wires into sound card , and another time with integrated sound....with intergrated sound,,i get the back two speakers,,the sound card, the front 2 speakers work...the supwoofer works ....any idea why i cannot get all 4 to work???
     
    Last edited: Feb 3, 2014
  14. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    This sounds more like a configuration issue within the OS than a hardware problem.

    [​IMG]
     
  15. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    After years of being undisturbed and working perfectly, I unplugged the wall plug of my v2.4, 4.1's and they are now unlistenable. Music plays on all channels but extremely muted and distorted, and there is an intermittent buzzing.

    I've followed many of the instructions in these posts.

    On the DC-DC converter

    measured R26: 48 Kohm, casing cracked but OK
    measured R27: 5 ohm, OK
    measured R1 and R2 on: 476 ohm, OK

    On the Digital converter
    measured R12: 680 ohm, signs of heat damage but OK

    measured R1 and R2, which wasn't instructed, but this is where I found the only issue,
    R2 was ok at 10 Kohm, but R1 was 70 kohm instead of the 36.5 kohm (which is what is called out on the circuit diagram and by the color code on the resistor). R1 is close to the very hot R12, so I figure it may have been damaged by heat. The resistor appears ok though, and I would think that it would read as infinite if truly damaged. Am I missing something?

    The only other potential problem is the DIN pod, but since it happened based on a power surge from plug un-plug, I figured it was somewhere in the sub circuitry.
    Any thoughts? suggestions? Thanks.
     
  16. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    I just took things apart, and when with the Digital Converter disconnected R1 is 36.5 Kohm. Connected it was measuring 7 Kohm (not 70 kohm as stated previously).
    Back to square one!
    Possibly a diode, mosfet, or capacitor issue. Not sure how to measure these, i'll check youtube.
     
  17. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    Do you have a multimeter that can test capacitance and diodes?

    The buzzing noise can be the rectifier failing and allowing AC to pass through. You will have to remove the part in order to test it. You can use a simple DC multimeter set to voltage and check the voltage drop across two pins. It should read near 0VDC in one direction and a higher voltage when you switch your testing leads.

    Have you looked at the pre-amp yet? It is located withing the pod with the sub, surround, and volume knobs.

    [​IMG]
     
  18. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    I do have a multimeter and I figured out how to test diodes/capacitors (youtube). So far I haven't located any that are clearly faulty, however I noticed that two of the capacitors have leaked (see pics), not sure if this would cause my problem. They seem to hold voltage which slowly drops off, as youtube advised they should.

    http://i62.tinypic.com/2i6c4ye.jpg

    http://i57.tinypic.com/282fecl.jpg

    I will look for and test the rectifier, the"tall, thin, black block with a hole through it and 4 leads.

    I opened up the POD/pre-amp, nothing looked damaged. I read that people fixed issues by using electrical cleaner on the pots. I don't have cleaner, but if I get some where should it be sprayed. Enough questions from me.
     
    Last edited: Feb 20, 2014
  19. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    Capacitors in a DC circuit are often used to filter out AC voltage, which is often the cause of buzzing noise. I'd definitely replace both of those capacitors, plus the cooked resistors while I was at it.

    [​IMG]
     
  20. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    You will want to spray around the pots themselves, trying to get at the internal bits if possible. You are trying to clean the interface between the mobile pot knob and the contactor strip that it rides along.



    [​IMG]
     
  21. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    Tested the bridge rectifier (in circuit) and it works.

    I'm going to try swapping out the capacitors and resistor and cleaning the pots before I go any further with the rectifier.

    Thanks for all the help.
     
  22. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    Just an update, I replaced only the resistors (r12 and r26) and no other components...and...SUCCESS!!!
    So, even though I was getting close to nominal measurements on these resistors (that looked damaged) replacing them corrected the buzzing! So if your resistors look crispy, I would replace them despite ok readings.
     
  23. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    Just a quick question, what type of meter did you use to test them and how did you perform the test. I'm curious to know if this could have been identified if we had tested the resistor while it was heated up (say, held over a hot plate or using a heat gun), or potentially build a simple circuit that simulated the load that it would normally see in the actual circuit.

    Ok, enough of that. I will take my engineer's hat off now. :D



    [​IMG]
     
  24. Frito_B

    Frito_B n00bie

    Messages:
    6
    Joined:
    Feb 18, 2014
    Just a cheap and basic multimeter at room temperature.
     
  25. hotsho111

    hotsho111 n00bie

    Messages:
    6
    Joined:
    Oct 8, 2011
    Hey everyone, my 4.1's continue to try and die and I continue to refuse to let them.

    I noticed when I turned them off the red light wasn't showing on the control pod and the speakers were buzzing a bit. I checked the amp which was pretty warm and immediately disconnected it. I could smell a bit of burning smell and today after checking the board over it looked like the R27 resistor was the culprit. It was reading 5ohms so I turned the speaker on real quick and the control pod light was green but quickly went away and I immediately unplugged the speaker again. The R27 resistor looked a bit worse than it did yesterday so hopefully replacing that solves the problem

    It looks like one of the surface mounts on my board went at some point as well(c207):
    [​IMG]
    You can see the repair for c309 and c310 that went a few years ago.

    I've found that piece in this diagram (bottom left area marked c7): http://www.thompdale.com/bash_amplifier/4-1/4-1_amplifier_993x641.gif
    It looks like its 20v but I'm not sure what the u1:3 5532 means.

    Anyone know what part that should be?

    I also need to replace the R27 resister and was planning on going with a 4.7ohm 2 watt resistor (http://www.digikey.com/product-detail/en/PR02000204708JR500/PPC4.7W-2CT-ND/597408) . That should be safe right?

    The unit is getting a bit old now and 2 of the capacitors are leaking so I'm going to replace those as well.
     
  26. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    U1:3 is an IC. You will see an IC next to the bad cap with "5532" printed on it. Don't worry about it for now. Trying to test it without its own schematic and/or special tools is nigh impossible.

    If you look at the bottom of the schematic that you posted, you will see that all SMT resistors are size 1206 and capacitors are size 0805 unless otherwise noted. Therefore, C207 is an 0805-sized cap. As far as the F rating, I can't find any info on this. I would recommend that you take off C107, C307, C407, etc and measure them. They should all be the same value.

    I'd stick to the recommendation by thompdale.com. Two, 10-ohm, 5%, 1W.
     
  27. hotsho111

    hotsho111 n00bie

    Messages:
    6
    Joined:
    Oct 8, 2011
    I saw some discussion on that earlier and I believe mine is a single 4.7 ohm 1 watt resistor and not two.

    Here's a picture of the resistor:
    [​IMG]

    Edit: Checking out that diagram, it does seem to label R27 as "0.1" but I'm not sure of the units. When I measured the resistance on mine it came up as 4.7-5ohms

    Edit 2: It looks like the v2-400 uses the pair of resistors but the v4.1 (which is what I have) looks like it uses a single resistor
     
    Last edited: Mar 12, 2014
  28. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    What board is the photo from? Is this the board? If so, you should have 3 other resistors (R9, R15, R21) of the same value nearby that you can remove and test.

    [​IMG]
     
  29. hotsho111

    hotsho111 n00bie

    Messages:
    6
    Joined:
    Oct 8, 2011
    I'm actually not sure. I believe it's the DC-to-DC board, but in the diagram I can't find an r27 resistor.

    In that picture the board to the left is the amplifier board

    Edit: oh wait, that is the DC-to-DC board. I found the r27 resistor in the bottom left of that diagram. Looks like it is 4.7ohm 1/2watt
     
  30. usedmedia

    usedmedia n00bie

    Messages:
    6
    Joined:
    Dec 30, 2009
    So I have a set of these that I've been using for the past 12+ years. They have been wonderful during this time, but very recently the subwoofer began to rattle. It was bad enough that I couldn't enjoy games or music anymore, so I hooked up some cheap PC speakers in the meantime.

    Is my sub blown? I opened it up and poked around, but wasn't sure what to look for. Is this worth fixing or should I move on?
     
  31. mngl1500

    mngl1500 2[H]4U

    Messages:
    3,332
    Joined:
    Feb 28, 2005
    Free local pickup one set of semi working Klipsch 4.1.
    I replaced them like two years ago but kept them in the closet to fix them some day. Wife wants them gone.

    By semi working I means they have hey a very quiet now and one of the rears way not working.

    I live in IGH, MN and work in Bloomington, MN. Send me a PM if interested.
     
  32. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    A rattle in the sub can be easy to fix or costly. More than likely, you have something loose inside the enclosure. I have a larger open-ported sub on my HTPC, which my young daughter likes to use to store random bits of trash and toys. That thing will rattle like crazy and I will have to remove the speaker to fish out all the trash. I'd suggest that you do something similar and look around inside for something loose.


    On the flip side, a sub rattle can also be caused by overdriving it and/or it mechanically failing. Inspect the spider (the part connecting the frame and the speaker cone), the cone, and the magnet assembly.

    [​IMG]
     
  33. usedmedia

    usedmedia n00bie

    Messages:
    6
    Joined:
    Dec 30, 2009
    Thanks for the suggestions. When I opened it up everything seemed nice and tight, and I didn't notice anything loose. When I pushed down gently on the speaker cones, they would spring back up.

    At this point I may just go ahead and invest in a regular 2.1 speaker setup. I have a spare Denon receiver, so I might as well use it. Is there any market for these older Klipsch 4.1 sets? The control pod and the satellites all work fine, and someone who is handier then me could probably fix the sub rattle.
     
  34. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    I can't say if there is a market for them, but I'd love to find another setup for my kids' PC. Take a look around Ebay, craisgslist, etc.


    [​IMG]
     
  35. hotsho111

    hotsho111 n00bie

    Messages:
    6
    Joined:
    Oct 8, 2011
    If only I was in MN :D

    For my issue (and anyone that sees this in the future), it looks like the r27 resistor goes when there are some problems with the nearby capacitors so I'm gonna try replacing them (they are 47uf 50v) as well as the resistor.

    It looks like the surface mounts are 131nF so a replacement of 150nF (.15uF) @ 100v should be a good replacement.

    Gonna try replacing everything so I'll let you know how it goes
     
    Last edited: Apr 2, 2014
  36. hotsho111

    hotsho111 n00bie

    Messages:
    6
    Joined:
    Oct 8, 2011
    Replaced the two capacitors, the r27 resistor and the c207 surface mount and everything works again!
     
  37. Catboxer

    Catboxer Gawd

    Messages:
    1,008
    Joined:
    Feb 1, 2003
    Gonna resurrect this thread to say my vintage '99 4.1s finally started acting up. After 15 years it's hard to complain, and I don't think the amp has ever been turned off unless I was moving. I'm down to one channel with full volume and the other with 25% output. It's the cheap volume pot, this problem was fairly common for my system. Giggling the volume pot used to bring the other channel back. Deoxit hasn't helped, I can feel the wipers are no longer making good contact. Anyone locate a source to replace the volume pot?
     
  38. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    I'd like to know of a source for the pots, too. Mine are getting sloppy and might need replacing soon.

    As a side note, the foam surrounds on my subwoofer drivers fell apart the other week. I purchased some new ones on amazon and replaced the surrounds. My bass is back and better than ever.
     
  39. IM0001

    IM0001 n00bie

    Messages:
    10
    Joined:
    Feb 9, 2015
    Well time to dig up this old post.
    My 4.1 v.2-400's have finally tossed in the towel. Worked fantastic since 2000 and now when they are plugged into power, you can hear a electronic buzzing that isn't static, but appears to come from the area with the copper wire tower. (Still rusty with my electronics identification so bear with me.)

    My R26 Resistor was shedding itself and seemed to be way off on its readings so I replaced that and no dice, The R12 looked like its been cooking for years, and the circuit board around the hole closest to the edge has cracks coming out from around it with one crossing over the top hole of the diode next to it. Not sure if that would affect the copper underneath or not but for the life of me I cannot find a replacement board anywhere for the amp of the 4.1 system.

    The R12 reading is only throwing up 633 when I know its supposed to be 680. Could that small of variance cause the digital buzzing?

    Every other resistor and cap seems to check out. All the caps look brand new with no bulging and all the R1/R2 etc resistors all appear to look new and hit right on the money for their readings (however the color codes continue to confuse me a bit on some. Ones that are coded I believe to be 36K end up being 4.7K on the dot...?)

    I will post a few pictures later as my Amp looks different in a couple ways then all the ones posted here and the diagrams appear to be off a bit from what I seem to have in parts. Even the BASH board is a XX12 vs all the diagrams showing XX11 and less.
     
  40. titan97

    titan97 Limp Gawd

    Messages:
    492
    Joined:
    Sep 27, 2004
    Despite the age of this thread, I still subscribe to it and try to help out when I can.

    The bridge rectifier might be bad. This is allowing AC voltage through your system, which is causing the buzz, despite the best efforts of the caps and resistors to filter out the noise. Mine failed a couple of years ago. Also, read the comments in the thread by Frito_B. He, too, had some buzzing noise which he fixed by replacing some resistors.

    When you tested the components, did you remove them from the board?