Polk PSW111 sub-woofer - Heartbeat

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  • Fabio_rm
    Fabio_rm Posts: 39
    edited November 2022
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    The critical capacitors are C38 and C39, before the voltage regulators for the OPs, followed by those which, like these, levelling the rectified PWM voltage C14, which feeds the final power mosfets, and C12 which feeds the voltage regulator for the PWM controller. These can all be replaced with Panasoni FR-A seie. Good thing wil be replace C24 also, the large 400V capacitor that levels the mains voltage, not needed at low impedance for it but a good ripple current, long life and 105°C. After the transistors voltage regulators, there are less critical capacitors, C3, C7 and C22, but if they have a long life it's better too, I also used FR-A for these, considering that in the order I had to buy at least 5 of each type. These mentioned are all the capacitors on the power supply, if you don't find capacitors of the same identical capacitance value, you can easily use slightly higher ones, of different brands, but reliable brands, the important thing is that they have low impedance, long life, 105°C, are physically compatible and of course with right voltage. The other capacitors, including the bipolar ones in the preamplifier stage, generally don't give problems but if you want to change those too, it is no bad.
    However, I reiterate that it is the combination of the original Chinese capacitors and the alwais power on, are the reasons that these in this subs cause quickly die. No complicated switch-on schemes need, just one 5Vdc relay and two diodes 1N4007, drived from the integrated amplifier's service sockets and generic little power supply (also a smartphone usb pover suppli cam be userd), or via the AV receiver's USB port. The heat sink, it's not essential but add it will be good. I recycled the one from an old CPU slot 1, cost zero.
    PS: I also design amplifiers and I'm not a beginner, I graduated in electronics in 1980 ... I'm certainly better in electronics than with English ... so sorry for the typos :)
    Post edited by Fabio_rm on
  • Walterx79
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    Salve a tutti, sono nuovo del Forum e non ho tanta competenza in materia, quindi sarebbe straordinario se riusciste ad aiutarmi. Ho un Subwoofer Polk Audio PSW111 acquistato tanti anni fa, collegandolo alla 220v salta il fusibile, va in corto circuito. L'ho portato da un Elettronico a riparare ma non hanno potuto fare niente, mi hanno detto che si è bruciata la scheda piccola sulla scheda grande e non c'è niente da fare. Allego foto della scheda bruciata, potreste aiutarmi a trovare la scheda completa o il componente bruciato? Grazie
    cfkwjrhoqul7.jpeg
    fd00s8hl5whv.jpeg
    jrbhahtup9ca.jpeg
    z6u3f9i4mj67.jpeg



  • Fabio_rm
    Fabio_rm Posts: 39
    edited December 2022
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    Walterx79 wrote: »

    The board you see in the pics is different from the one you see in the pics of other users, as you can see yourself by the pics, This reinforces my hypothesis that there are different versions of the PSW111 with different amplifiers. The other users' SUBs have a card that is completely similar to the one fitted to my PSW110, probably they have the same wiring diagram, even if the PSW111 is declared as 150W RMS while the PSW110 is 100W RMS, the only visible difference is the diode rectifier of the power stage, probably also change the mosfet transistors but it is only a hypothesis, I could not verify it. I don't think it is possible to find the small card you are talking about, on the other amplifiers there is also a small card, which generates and regulates the PWM signal and drives the mosfet on the transformer primary, I also assumed that in my SUB it was that was bad, but by changing the capacitors and a bad mosfet the SUB started working again. Unfortunately your defect is different and the board is different too, I don't have the wiring diagram to make hypotheses and I can't help you (I'm in Italy too but you should try to write in English to be understood by others, maybe someone has yours same amp and fixed it somehow).
    Post edited by Fabio_rm on
  • bthnc
    bthnc Posts: 1
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    Fabio_rm wrote: »
    Walterx79 wrote: »

    The board you see in the pics is different from the one you see in the pics of other users, as you can see yourself by the pics, This reinforces my hypothesis that there are different versions of the PSW111 with different amplifiers. The other users' SUBs have a card that is completely similar to the one fitted to my PSW110, probably they have the same wiring diagram, even if the PSW111 is declared as 150W RMS while the PSW110 is 100W RMS, the only visible difference is the diode rectifier of the power stage, probably also change the mosfet transistors but it is only a hypothesis, I could not verify it. I don't think it is possible to find the small card you are talking about, on the other amplifiers there is also a small card, which generates and regulates the PWM signal and drives the mosfet on the transformer primary, I also assumed that in my SUB it was that was bad, but by changing the capacitors and a bad mosfet the SUB started working again. Unfortunately your defect is different and the board is different too, I don't have the wiring diagram to make hypotheses and I can't help you (I'm in Italy too but you should try to write in English to be understood by others, maybe someone has yours same amp and fixed it somehow).

    I have the same PSW111 that was posted in the pics by Fabio — stumbled on this thread because I finally had some time to crack open my very old PSW111 to see if any caps needed replacement as it isn’t working too well — occasional hum even with nothing connected. I’ll probably trash it because nothing is jumping out at me and likely not worth the time. The design seems quite different.
  • pitdogg2
    pitdogg2 Posts: 24,585
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    They're not worth taking the time and effort to fix. Buy a better sub built with better parts. The parts, shipping and if your time is worth anything at all you've eclipsed the cost of the original price of purchase.
  • Fabio_rm
    Fabio_rm Posts: 39
    edited December 2022
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    Walterx79 wrote: »

    I have the same PSW111 that was posted in the pics by Fabio — stumbled on this thread because I finally had some time to crack open my very old PSW111 to see if any caps needed replacement as it isn’t working too well — occasional hum even with nothing connected. I’ll probably trash it because nothing is jumping out at me and likely not worth the time. The design seems quite different.

    This is the pcb of my PSW110. I replaced first the capacitors (in the red cirlcles), those often cause the knowed heartbeat problem, after I replaced also all othe power supply electrolytics capacitor (in the jellow circes), finally I add additional heat sink (but this not necessary) 2rsaxw9npbjk.jpg
  • benjaro
    benjaro Posts: 3
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    Polk is replacing my PSW111 (under warranty) with a new one because of the heartbeat issue. Is there any reason to believe this replacement will have better capacitors or a better amp? Or will I have the exact same problem 3-4 years from now.
  • stevep
    stevep Posts: 328
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    Can't speak to the latest replacement parts but the Polk CS supplied amp for mine only lasted about that long before it too went bad.
  • Fabio_rm
    Fabio_rm Posts: 39
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    benjaro wrote: »
    Polk is replacing my PSW111 (under warranty) with a new one because of the heartbeat issue. Is there any reason to believe this replacement will have better capacitors or a better amp? Or will I have the exact same problem 3-4 years from now.

    If the amplifier is the same, I can't know but it's probable, even if the capacitors are better the life is limited by the fact that the sub is always powered, the only expedient to lengthen the life is to switch it off when not in use. I made a small circuit with a relay that is activated only when I turn on the stereo amplifier or AV receiver, it's a simply thing but I realize that not everyone is able to build it, in this case you have to use a power strip with a switch that powers both the stereo and the sub
  • gp4jesus
    gp4jesus Posts: 1,969
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    Fabio_rm wrote: »
    The critical capacitors are C38 and C39, before the voltage regulators for the OPs, followed by those which, like these, levelling the rectified PWM voltage C14, which feeds the final power mosfets, and C12 which feeds the voltage regulator for the PWM controller. These can all be replaced with Panasoni FR-A seie. Good thing wil be replace C24 also, the large 400V capacitor that levels the mains voltage, not needed at low impedance for it but a good ripple current, long life and 105°C. After the transistors voltage regulators, there are less critical capacitors, C3, C7 and C22, but if they have a long life it's better too, I also used FR-A for these, considering that in the order I had to buy at least 5 of each type. These mentioned are all the capacitors on the power supply, if you don't find capacitors of the same identical capacitance value, you can easily use slightly higher ones, of different brands, but reliable brands, the important thing is that they have low impedance, long life, 105°C, are physically compatible and of course with right voltage. The other capacitors, including the bipolar ones in the preamplifier stage, generally don't give problems but if you want to change those too, it is no bad.
    However, I reiterate that it is the combination of the original Chinese capacitors and the alwais power on, are the reasons that these in this subs cause quickly die. No complicated switch-on schemes need, just one 5Vdc relay and two diodes 1N4007, drived from the integrated amplifier's service sockets and generic little power supply (also a smartphone usb pover suppli cam be userd), or via the AV receiver's USB port. The heat sink, it's not essential but add it will be good. I recycled the one from an old CPU slot 1, cost zero.
    PS: I also design amplifiers and I'm not a beginner, I graduated in electronics in 1980 ... I'm certainly better in electronics than with English ... so sorry for the typos :)

    @Fabio_rm:
    Un grande caloroso benvenuto nel forum di Polk. Sono sicuro che puoi aiutare Walterx79 molto più di me.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • gp4jesus
    gp4jesus Posts: 1,969
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    Walterx79 wrote: »
    Salve a tutti, sono nuovo del Forum e non ho tanta competenza in materia, quindi sarebbe straordinario se riusciste ad aiutarmi. Ho un Subwoofer Polk Audio PSW111 acquistato tanti anni fa, collegandolo alla 220v salta il fusibile, va in corto circuito. L'ho portato da un Elettronico a riparare ma non hanno potuto fare niente, mi hanno detto che si è bruciata la scheda piccola sulla scheda grande e non c'è niente da fare. Allego foto della scheda bruciata, potreste aiutarmi a trovare la scheda completa o il componente bruciato? Grazie
    Un grande caloroso benvenuto nel forum di Polk.

    I’m gonna test my Duolingo-aquired Italian to translate. I’ll cheat* using a translator app only when necessary. Sono sicuro che Fabio ti sarà più di aiuto

    “Salve a tutti, sono nuovo del Forum…”
    Hello to everyone. I am new to the forum…

    “…e non ho tanta competenza in materia*,…”
    …and I don’t have much knowledge in the subject.

    “Quindi* sarebbe* straordinario* se riusciste ad aiutarmi.”
    It would be great if you could help me.

    “Ho un Subwoofer Polk Audio PSW111 acquistato tanti anni fa,…
    I have a Polk Audio sw PSW I picked up many years ago…

    “…collegandolo* alla 220v salta il fusibile, va in corto circuito.”
    …connecting* it to 220V blows the fuse, a short circuit.

    “…. L'ho portato da un Elettronico a riparare ma non hanno potuto* fare niente,…”
    I brought it to Electronic repair but they could not do anything.

    “…mi hanno detto che si è bruciata* la scheda* piccola sulla scheda grande e non c'è niente da fare.
    …they told me that the small PC on the big PC is fried and can’t do anything.

    “Allego foto della scheda bruciata,…”
    Here is a picture of the burned PC

    “potreste aiutarmi a trovare la scheda completa…
    Can you help me find a complete PC…

    “…o il componente bruciato? Grazie”
    …or the burned components? Thank you.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • Fabio_rm
    Fabio_rm Posts: 39
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    gp4jesus wrote: »
    @Fabio_rm:
    Un grande caloroso benvenuto nel forum di Polk. Sono sicuro che puoi aiutare Walterx79 molto più di me.

    I'm not sure if the PSW111 always used the same amplifier plate. I have seen some photos of the amplifier, taken by some users here on the forum, in which the pcb of the psw111 is the same as that of the psw100, despite the fact that the first is declared as 150W RMS and the second 100W RMS, visually the only difference is the diode that rectifies the voltage arriving at the mosfet terminals, whose case is different, I deduce that the circuit is the same but with different components, for example also the power stage mosfets, but it is only a deduction, they are covered by the clip fixing them to the heatsink. Instead from the pics posted by @Walterx79 the amplifier looks like another version, maybe more old, certainly different from the one I have in the PSW110. Having said this, it is highly probable that what the repairman told him is true, the fault is probably on the primary of the PWM transformer, the main defendants may be the mosfet that drives it and the PWM controller card, but I think it cannot be found. I guess the technician tested the other components, even if sometimes the technicians tell lies, when a job is complicated they prefer to send the customer away. What I can suggest to @Walterx79 and adapt another amplifier board, or, ask among the users of the forum if someone can send them a defective board with the heartbeat that they no longer use, the heartbeat is instead easily repairable by changing the capacitors that we know. For the rest it is quite difficult to make a diagnosis through a forum and I imagine that he is not in Rome like me but in some other part of Italy.

  • benjaro
    benjaro Posts: 3
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    benjaro wrote: »
    Polk is replacing my PSW111 (under warranty) with a new one because of the heartbeat issue. Is there any reason to believe this replacement will have better capacitors or a better amp? Or will I have the exact same problem 3-4 years from now.

    So...when Polk send me my replacement PSW111, does anyone want to buy it from me? I don't have the skills to replace capacitors myself, but I also don't want to be stuck in this same position 3 years from now. P.S. I'm in Toronto, Canada.
  • Fabio_rm
    Fabio_rm Posts: 39
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    benjaro wrote: »
    So...when Polk send me my replacement PSW111, does anyone want to buy it from me? I don't have the skills to replace capacitors myself, but I also don't want to be stuck in this same position 3 years from now. P.S. I'm in Toronto, Canada.

    I don't know if I misunderstood, Polk send you a new full SUB and leave you with the old one? Or just the amp? If you still have the defective SUB, you can put it up for sale on Ebay or other sales platforms. The heartbeat defect is quite well known and can usually be fixed with the usual repair, replacing the two capacitors that rectify the op amp supply, so I think you can easily sell it as defective. If you weren't in another continent I would buy it, I have a PSW110 but I need a more compact woofer, and I can repair it myself, unfortunately shipping costs would exceed the cost of the SUB.

  • benjaro
    benjaro Posts: 3
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    Fabio_rm wrote: »
    benjaro wrote: »
    So...when Polk send me my replacement PSW111, does anyone want to buy it from me? I don't have the skills to replace capacitors myself, but I also don't want to be stuck in this same position 3 years from now. P.S. I'm in Toronto, Canada.

    I don't know if I misunderstood, Polk send you a new full SUB and leave you with the old one? Or just the amp? If you still have the defective SUB, you can put it up for sale on Ebay or other sales platforms. The heartbeat defect is quite well known and can usually be fixed with the usual repair, replacing the two capacitors that rectify the op amp supply, so I think you can easily sell it as defective. If you weren't in another continent I would buy it, I have a PSW110 but I need a more compact woofer, and I can repair it myself, unfortunately shipping costs would exceed the cost of the SUB.


    Yes, exactly. They are sending me a completely new sub and now I have a broken one sitting at home and I can’t repair it myself.

  • Fabio_rm
    Fabio_rm Posts: 39
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    benjaro wrote: »

    Yes, exactly. They are sending me a completely new sub and now I have a broken one sitting at home and I can’t repair it myself.

    If Polk assistance doesn't ask for your SUB back and the defect is the heartbeat, instead of taking it to the garbage dump, have it repaired by any technician, as long as he has the necessary tools to desolder and replace two capacitors (even if it would be better change all the supply capacitors) and then resell it, or sell it as defective at a bargain price, at least give it away for free, the defect is known and it is known that it is easy to repair. For reasons of space I would like to replace my repaired PWS110 with a PSW111, even if it is defective, I know how to fix it myself, but we are too far away and it would cost more to ship than the SUB.
  • cynic
    cynic Posts: 1
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    fsol wrote: »
    I managed to replace the capacitors without removing the board which seems to be really hard. For doing this, I bent the capacitors so that a little bit of their wire stays out, and then pulled them out, and soldered the new capacitors to those wires. Works perfectly in my case. Thanks again for your life saving discovery about changing these capacitors.

    uh7j0n232qqq.jpeg

    g6eivobs2ili.jpg
    At the risk of being trolled I am submitting my fix - Couldn't get the board out AND couldn't solder to the existing wires of the suspected failed caps (I tried but me dumb)...So the last attempt was to use heat shrink (with NO soldering) and a BBQ lighter - in my case it worked! Put the amp board to power and all looked good - steady green light, so attached the subwoofer to the board and plugged into the receiver - and back to a working Sub! Now I got 2 cause I just got a new Klipsch 12" inch subwoofer off the Amazon - At any rate, if there are non electronic type people out there - this 2$ caps and $5 Bic BBQ lighter (for the heat shrink and warming up the board) worked for me...
  • jgerr
    jgerr Posts: 1
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    Clipdat wrote: »
    My time and sanity is worth spending more than $250 on a sub that won't **** the bed after a few years.

    If you spend more up front, you get more in the long run. For example I have a Velodyne CT-100 circa late 1990s that still works perfectly.

    I love the "I'm richer than you and my time is worth more than yours" comments on forums. I bought one of these because it's for my home office...it seems like a nice little sub for that use.
  • Clipdat
    Clipdat Posts: 12,608
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    Cool I hope it lasts 20 years.
  • boston1450
    boston1450 Posts: 7,474
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    jgerr wrote: »
    Clipdat wrote: »
    My time and sanity is worth spending more than $250 on a sub that won't **** the bed after a few years.

    If you spend more up front, you get more in the long run. For example I have a Velodyne CT-100 circa late 1990s that still works perfectly.

    I love the "I'm richer than you and my time is worth more than yours" comments on forums. I bought one of these because it's for my home office...it seems like a nice little sub for that use.
    12+ years ago i wish i listened to advice like that. I went around in circles & it cost me way more.. Since then I process what others have to say. Probably because they have been there & done that B)

    ..
    ..
    ..
    Randy/Maine
  • Fabio_rm
    Fabio_rm Posts: 39
    edited December 2023
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    cynic wrote: »
    At the risk of being trolled I am submitting my fix - Couldn't get the board out AND couldn't solder to the existing wires of the suspected failed caps (I tried but me dumb)...So the last attempt was to use heat shrink (with NO soldering) and a BBQ lighter - in my case it worked! Put the amp board to power and all looked good - steady green light, so attached the subwoofer to the board and plugged into the receiver - and back to a working Sub! Now I got 2 cause I just got a new Klipsch 12" inch subwoofer off the Amazon - At any rate, if there are non electronic type people out there - this 2$ caps and $5 Bic BBQ lighter (for the heat shrink and warming up the board) worked for me...

    Get out the board don't seems to me so hard, simply unscrew the screws, the sub have the vibrations that can be generated inside a SUB would require a more stable solution, but while it lasts, enjoy it

    Post edited by Fabio_rm on