Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 10 of 10
  1. #1

    Member Sales Rating: (0)

    Join Date
    Jan 2012
    Location
    Ann Arbor
    Posts
    5

    Default Polk Newbie, need help with 7B's

    I have been collecting and refurbishing speakers for the past ten years or so, mostly AR, KLH, Advent, etc. I just came upon a pair of 7B's, they are my first Polk speakers. One of the speakers works well, while the other does not put out any sound. After opening it up, I was immediately stuck as the crossover is quite different then any that I have ever worked on. Could someone help me with getting into the crossover? It appears that there are a couple of circular boards that are snapped together, do I just pull up on the upper board until it snaps free? I just want to make sure that I don't cause any damage to it while trying to get at it.

  2. #2

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,287

    Default

    At the top of the standoffs are two angled pieces, pinch them together while lifting up on the board slightly until all the standoffs are free, then lift the board completely off.
    '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 turd by the clean end."

  3. #3

    Member Sales Rating: (0)

    Join Date
    Dec 2011
    Location
    Feeding Hills, MA
    Posts
    2,326

    Default

    Quote Originally Posted by F1nut View Post
    At the top of the standoffs are two angled pieces, pinch them together while lifting up on the board slightly until all the standoffs are free, then lift the board completely off.
    I sometimes find it easier to remove the standoffs from the bottom. This is especiallty true with the newer, larger SDA boards. Some of the standoffs are inaccessible from the top, due to being sandwiched between other components. Use a pair of needle-nose pliers, and gently squeeze the bottom prongs together and push the stand-off upwards.
    Charles218, be very carefull with the crossover, when the two parts are separated. Theres a single solid wire coming up from the coil that's soldered to the bottom of the circuit board. If you move the two parts around too many times, the wire and solder point can become weakened, and sometimes breaks off. If that happens, you'll have to clean a new section at the end of the coated coil wire, and resolder the connection.
    Last edited by westmassguy; 06-17-2013 at 07:03 AM.
    Home Theater/2 Channel:
    Front: SDA-2ATL http://www.polkaudio.com/forums/show...ished...Almost
    Center: Custom http://www.polkaudio.com/forums/show...hannel-Project
    Surrounds & Rears: Custom http://www.polkaudio.com/forums/show...rround-Project
    Sonicaps, Mills, RDO-194s-198s, Dynamat, H-Nuts, BH5
    Pioneer Elite VSX-72TXV, Carver PM-350, SVS PB2-Plus Subwoofer


    www.dhsspeakerservice.com

  4. #4

    Member Sales Rating: (0)

    Join Date
    May 2009
    Location
    Plano, TX
    Posts
    272

    Default

    The standoff's are the easy part! You need to decide if you want to remove/desolder the six wires attached to the bottom; otherwise you have to go in from the front and unhook them from the tweeter/driver. In either case, I don't think you can get around at least removing the (+) and (-) wires from the PCB if you want to do any real work on it (like remove a bunch of parts).
    Good luck!
    Yamaha DSP-A1 Integrated Amp
    (4) Polk Monitor 10B's w/SoniCaps, Mills, and RDO-194 tweets (R/L F/R)
    (2) Polk Monitor 4's w/peerless tweets (dual centers)
    B&O TX2 Turntable
    Nakamichi Cassette Deck 1
    Pioneer CLD-99 Elite LD
    Samsung BD-P2550 Blu-Ray/DVD
    LG LST-3410a OTA DVR
    Princeton AF3.0HD Monitor
    Optoma HD65 Projector

  5. #5

    Member Sales Rating: (0)

    Join Date
    Jan 2012
    Location
    Ann Arbor
    Posts
    5

    Default

    Thanks to each of you for your timely and helpful responses. I wanted to make sure that I didn't mess things up, but after I got into it I could see that it was quite straight forward.

    Peeking inside didn't help me along with the problem of no sound. I did the battery trick on each of the drivers and they appear to work. I was hoping that I would find something obvious that would cause both drivers to be silent. I have always replaced the capacitors when I work on vintage speakers as I know that they go bad. Is it possible for a bad cap to cause both drivers to not function?

    I'm not very experienced when it comes to circuitry, but can check for continuity, resistance, and a few other basic procedures. Does anyone have any suggestions on what I might look for?

    Charles

  6. #6

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,287

    Default

    Start at the binding posts and trace the circuit step by step until you find the problem.
    '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 turd by the clean end."

  7. #7

    Member Sales Rating: (0)

    Join Date
    Dec 2011
    Location
    Feeding Hills, MA
    Posts
    2,326

    Default

    Quote Originally Posted by F1nut View Post
    Start at the binding posts and trace the circuit step by step until you find the problem.
    ^^^^^^^^^^
    This
    If the tweeter AND woofer are not functioning, it should be quite easy to find the break in the circuit
    Home Theater/2 Channel:
    Front: SDA-2ATL http://www.polkaudio.com/forums/show...ished...Almost
    Center: Custom http://www.polkaudio.com/forums/show...hannel-Project
    Surrounds & Rears: Custom http://www.polkaudio.com/forums/show...rround-Project
    Sonicaps, Mills, RDO-194s-198s, Dynamat, H-Nuts, BH5
    Pioneer Elite VSX-72TXV, Carver PM-350, SVS PB2-Plus Subwoofer


    www.dhsspeakerservice.com

  8. #8

    Member Sales Rating: (0)

    Join Date
    May 2009
    Location
    Plano, TX
    Posts
    272

    Default

    It's got to be something where the (+) or (-) inputs come into the board. I had a "no bass" problem after I rebuilt mine and it turned out I had lifted the (+) pad when I was removing parts. Since you can't really "replace" the pad, I soldered the lead to another wire/pad on the same node.
    Yamaha DSP-A1 Integrated Amp
    (4) Polk Monitor 10B's w/SoniCaps, Mills, and RDO-194 tweets (R/L F/R)
    (2) Polk Monitor 4's w/peerless tweets (dual centers)
    B&O TX2 Turntable
    Nakamichi Cassette Deck 1
    Pioneer CLD-99 Elite LD
    Samsung BD-P2550 Blu-Ray/DVD
    LG LST-3410a OTA DVR
    Princeton AF3.0HD Monitor
    Optoma HD65 Projector

  9. #9

    Member Sales Rating: (0)

    Join Date
    Jan 2012
    Location
    Ann Arbor
    Posts
    5

    Default

    Thanks for the help with this, though now the issue is becoming murky. I am beginning to get mixed results and need to continue working on it. Earlier today, I was able to get the woofer working in the problem speaker, this after I replaced the 34 mfd capacitor. So this is a work in progress, made frustrating as I have so little time right now to devote to it.

    Charles

  10. #10

    Member Sales Rating: (0)

    Join Date
    May 2009
    Location
    Plano, TX
    Posts
    272

    Default

    Do you have an Ohm-meter (they can be had on the cheap @Radio Shack)? The circuit is simple enough that you can "Ohm out" each component/node. You've already demonstrated that either:

    1) you had a bad cap
    2) something wasn't making contact or you had a bad connection (solder)

    Continue through the circuit (as F1nut suggested) "Ohming out" each node; if that all makes sense, then you have another bad component (probably one of the other capacitors).
    Yamaha DSP-A1 Integrated Amp
    (4) Polk Monitor 10B's w/SoniCaps, Mills, and RDO-194 tweets (R/L F/R)
    (2) Polk Monitor 4's w/peerless tweets (dual centers)
    B&O TX2 Turntable
    Nakamichi Cassette Deck 1
    Pioneer CLD-99 Elite LD
    Samsung BD-P2550 Blu-Ray/DVD
    LG LST-3410a OTA DVR
    Princeton AF3.0HD Monitor
    Optoma HD65 Projector

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Similar Threads

  1. Polk Newbie - Monitor 10A's
    By chicks in forum Vintage Speakers
    Replies: 16
    Last Post: 01-16-2011, 11:28 AM
  2. Need Help Newbie and First Polk HT
    By kennethkars in forum Speakers
    Replies: 50
    Last Post: 08-06-2010, 10:58 AM
  3. Polk Sub newbie!
    By uiccracer in forum Subwoofer Hookup & Bass Management
    Replies: 1
    Last Post: 12-29-2007, 02:37 AM
  4. you might be a Club Polk newbie if....
    By danger boy in forum The Clubhouse
    Replies: 93
    Last Post: 12-18-2007, 09:39 PM
  5. Polk newbie, SDA-1C ??
    By 00p225 in forum Speakers
    Replies: 1
    Last Post: 01-22-2004, 08:56 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts