need help diagnosing MW8002 driver

RickDelRickDel Posts: 5
edited February 2014 in Troubleshooting
Hello, I have a pair of RT400 floor stand speakers, which contain MW8002 drivers. One of them has been vibrating and sounds blown, so I pulled it out to exam it. I see no visual damage and the multimeter test reads 3.5 - 3.6 on the Ohms.

I'm a newbie and have no real knowledge or experience with speakers. So, do you guys have any advise? Is this speaker salvageable?

Thanks!

Rick
Post edited by RickDel on

Comments

  • ken brydsonken brydson Posts: 6,391
    edited February 2014
    RickDel wrote: »
    Hello, I have a pair of RT400 floor stand speakers, which contain MW8002 drivers. One of them has been vibrating and sounds blown, so I pulled it out to exam it. I see no visual damage and the multimeter test reads 3.5 - 3.6 on the Ohms.

    I'm a newbie and have no real knowledge or experience with speakers. So, do you guys have any advise? Is this speaker salvageable?

    Thanks!



    Rick

    Welcome to Club Polk! It's probably blown but try rotating it 180 degrees and see if that solves the problem. Sometimes it does. If not, call CS and see if they still stock the drivers. Be sure to mention you're a forum member for a nice discount and free shipping. Good luck!
    HT/Main- Panny 50" G10 Plasma, Pioneer SC-1222k AVR, Panny DMP-BD60 BDP, Polk LS90 mains, CS350LS center, LS/fx side surrounds, LS50 surround backs, SVS 25-31PC+ sub, Harmony One

    Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t
  • RickDelRickDel Posts: 5
    edited February 2014
    Thanks for the quick reply. So, you mean to just rotate it 180° from it's original position (reinstall it upside down)?


    Can I ask you, isn't my multimeter reading correct? Wouldn't a 3.5 - 3.6 on a 4 ohm indicate it's working correctly? (again, I know NOTHING, just trying to follow along with others suggestion)

    Thanks again.
  • ken brydsonken brydson Posts: 6,391
    edited February 2014
    Yes, rotate and reinstall. The rest is above my pay grade. Just heard it works sometimes.
    HT/Main- Panny 50" G10 Plasma, Pioneer SC-1222k AVR, Panny DMP-BD60 BDP, Polk LS90 mains, CS350LS center, LS/fx side surrounds, LS50 surround backs, SVS 25-31PC+ sub, Harmony One

    Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t
  • F1nutF1nut Posts: 37,680
    edited February 2014
    A driver can read ok, but still have a rubbing voice coil. With the driver mounted, spread your fingers evenly around the cone, then gently push in and release. If you hear a scratching noise, you have a rubbing voice coil. It may also be a bad spider. Regardless, you need a new driver.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • kcoc321kcoc321 Posts: 1,771
    edited February 2014
    I did see a set of those on ebay last night..
    price wasn't too bad....you could make your $$ selling off the other parts.
    link
    http://www.ebay.com/itm/Polk-Audio-MW-8002-7-5-Woofer-Speaker-SL-5501-Tweeter-Wiring-for-RT-10-/301091371344?pt=US_Speaker_Parts_Components&hash=item461a71b950
  • RickDelRickDel Posts: 5
    edited February 2014
    Thanks for the help.

    This is my living room set up, not my HT, so I'll probably just swap them out with some older Polk bookshelfs I have.

    I've had these speakers for about 15+ years, but never abused them, so I'm a little disappointed they've failed me. My dad's still rocking a set of Kenwood speakers that are over 30 yrs old!
  • F1nutF1nut Posts: 37,680
    edited February 2014
    but never abused them

    Famous last words....LOL

    Doo-doo happens. It's only one driver, why not just replace it?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • RickDelRickDel Posts: 5
    edited February 2014
    Seriously, I've never played it very loud. I have a much larger set up for my HT, so that's the one that get's pushed.

    From what I've been reading, Polk discontinued the 7 1/2" MW8002 driver. I don't want to spend a lot of money, nor do I trust eBay. I'm wondering if I could use an 8" and modify the speaker boxes to accommodate it.
  • F1nutF1nut Posts: 37,680
    edited February 2014
    Did you test the driver as I suggested?
    Seriously, I've never played it very loud.

    Got a wife, kids?
    I don't want to spend a lot of money, nor do I trust eBay.

    Have you even looked at eBay to see what they sell for? PayPal has a money back guarantee, you've got nothing to lose.
    I'm wondering if I could use an 8" and modify the speaker boxes to accommodate it.

    You can't just slap any old driver in there.

    Not sure why you're fighting the idea of repairing the speaker the right way. After 15 years, I don't think you've got anything to complain about. Nothing lasts forever, except maybe those awful Kenwood speakers. :lol:
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


  • RickDelRickDel Posts: 5
    edited February 2014
    I just flipped the speaker over as you suggested and I haven't heard the muffled, vibrating sound yet. I'm still listening.

    As for your other comments. They are 15 years old, so I don't think it's worth my money to fix one driver because the other one could go next. I'd rather just spend my money on something new. But more importantly, these speakers don't get pushed, so I think I could get away with just swapping them out with the Polk bookshelfs I already own for free! (I could probably just remove the driver and no one in my house would ever know the difference)

    I'll keep listening, but if that's all it took to fix the problem.. THANK YOU!
  • nbrowsernbrowser Posts: 6,572
    edited February 2014
    RickDel, if you really like the speakers, it's worth repairing, I personally have a pair of Polk Monitors that date back to '79, if anything were to break in them I'd certainly fix them and even right now I'm planning modifications to them in the spirit of making them go another 30+ years. eBay and Paypal like F1 mentioned make any purchase done there as risk free as possible, and finding a replacement driver for a lot less than a new pair of speakers is always a plus.
    Living room: Samsung UN55KU7000 4K UHD HDR 55 inch TV, Marantz CD6004, Pro-Ject Debut Carbon, Parasound zPhono, Mac Mini, Oppo BDP-93, XBox One S 2Tb, Kenwood DPX792BH car deck for radio purposes, Marantz SR5010 AVR, Parasound HCA-1200II, Front SDA 2 modded with Larrys Rings and RD0-194-1 tweeters, Rear Onkyo SKF-4800 Towers, Center CSiA6, BOOM Tannoy TS2.12 Sub, Audioquest Evergreen interconnects just about everywhere except from AVR to amp, MIT Terminator 4, MIT AVT3 speaker cables with extra terminals covered up Monitor 5 Jr+ in the wings for a center channel.
  • ken brydsonken brydson Posts: 6,391
    edited February 2014
    A TON of us are running vintage. If you like them, well worth repairing...
    HT/Main- Panny 50" G10 Plasma, Pioneer SC-1222k AVR, Panny DMP-BD60 BDP, Polk LS90 mains, CS350LS center, LS/fx side surrounds, LS50 surround backs, SVS 25-31PC+ sub, Harmony One

    Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t
  • MrVideoMrVideo Posts: 1
    Just to add a breadcrumb here, I've had my RT400 units for 15 year. One MW8002 stopped working in 2007. Polk managed to find a replacement but the replacement just went bad here in 2017. I love these units and have the nice large matching center unit. Replacement drivers are $70 and well worth it to keep the system going IMHO.
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