One of my JBL L19 speakers is acting up. Please help...

Discussion in 'The Lansing Legacy' started by Mr.White, Feb 8, 2018.

  1. Beatnik

    Beatnik What's this ?

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    I had one tweeter not making good contact between the terminal and the brad they put it on with. Had to solder across them and it's been fine.
     

     

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  2. MCM_Fan

    MCM_Fan AK Subscriber

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    Things tend to rattle loose and become corroded over time. Glad it's working now. The L19s are great little speakers.
     
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  3. malden

    malden Addicted Member

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    I've experienced this several times with older JBL's. Making sure all of the contacts are clean and properly seated should be the first step in trouble-shooting problems.
     
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  4. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    If they use those slide-on lugs that are curled over on each side, sometimes they get loose. Here in MO they call it 'wallered out". :p A gentle squeeze with pliers will make it grip better.

    [​IMG]
     
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  5. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    The crimped on Fast-On connectors and their corresponding contacts on the drivers are not gold plated so they can corrode over time. Using a pair of pliers to pull off, crimp over the rolled contacts, and apply-reapply a few times will clean them. A small spray of DeOxit on them while attaching them will help as well. Same will also apply to the ring terminal that is sometimes used for the input terminal wiring .
     
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  6. Hajidub

    Hajidub Chihuahua/Pug = Chug Subscriber

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    I've owned and refoamed a set of these. All around I consider the L19 to be a top-notch bookshelf speaker and worth fixing if another issue arises. A VC issue with these, I had this issue, caused a very distinct metallic twang. If the VC was rubbing it should show up when ohming out the speaker with a meter. Glad it fixed, but don't be surprised if the issue comes back. I still think the issue was L-pad related somehow.
     
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  7. Mr.White

    Mr.White Super Member

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    Unfortunately the problem has returned. I tried removing the woofer again, recleaning the contacts and using a needle nose pliers to really tighten the connection. It was ok for a few songs and then the noise came back again.

    What to do next? As previously stated the problem followed the woofer when I switched them. Is it possible they need to be refoamed? Replaced?
     
  8. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    1. rotate the entire box 90 deg. at a time to see if it helps or changes the distortion. If one position improves it or makes it even worse, then you may have a sagging surround or spider which allows the voice coil to move to one side in the gap. There are ways to re-center the spider but its involved.

    2. double check the condition of the surround, either pinch it slightly or push gently on the roll to about 1/4 inch - it should spring back nicely. If it at all dents, crumbles, or doesn't spring back, it and the other driver should have their surrounds replaced with purpose fit new ones. When you bought them, had they been newly refoamed or refoamed a while back? Where do you live and what environmental conditions do these speakers sit in?

    3. Order / get from Amazon, Parts Express, or a local Guitar center some DeOxit D5 and use on the L-pad control on the speaker to clean the control, also useful for your controls on receivers and amps. This will ensure the pots are not a source of corrosion induced distortion.

    4. If you did move the woofer and the problem follows the woofer only, not the cabinet, I'd not think the crossover is the issue. OTOH, being OCD, I'd look carefully at all the solder joints and wiring connection points and clean them up, resolder them, and make sure the wiring is in good condition.

    If after all of the above, the woofer still is having problems, then I would consider the voice coil or spider to be a problem and it would normally need a recone - but hard to find NOS OEM JBL recone kits for this driver, and not inexpensive. Then I would consider buying a used and working 116A or 116H woofer from ebay that hasn't been messed with, and needs a surround replacement, or you could buy one already redone (makes it off time line from your current one though). That's why I suggest replacing the surrounds together. 116A/H drivers on Ebay or even here at AK (become a subscriber, put a WTB in Barter Town Parts and they may come out to play!) are not expensive.

    Good luck!
     
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  9. Beatnik

    Beatnik What's this ?

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    Tinsel lead maybe ?
     
  10. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Could be, so being handy with a soldering iron, some new solder wick and solder, and touching up the tinsel connections on the driver connections plus crossover might be helpful, although the crossover doesn't sound like its the issue specifically.
     
  11. Hajidub

    Hajidub Chihuahua/Pug = Chug Subscriber

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    Starting to sound like the previous owners refoam job is starting to fail. Order a new surround and redo. BTW, I've found the AAA battery method works well with tight JBL voicecoils. Mr. White is the sound close to a metallic twang when the bass note hits?
     

     

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  12. Mr.White

    Mr.White Super Member

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    Not really. It's more of a low tearing sound. Or the sound of someone lightly breathing through a baritone sax.
     
  13. Mr.White

    Mr.White Super Member

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    1. It's late and I just woke up so I will try rotating the speaker tomorrow during the day. I checked a diagram so I now know what terms like "spider" and "voice coil" refer to!

    2. The surround seems fine. It's still firm and springs right back all around. I see no damage. The seller told me that he had just refoamed them before I bought them. He fixes old equipment and resells on Craig's list. I live in Brooklyn, NY. These speakers are in my living room sitting on custom made wood stands. They have not ever been subject to extreme heat/cold conditions or a dirty/dusty environment since I've had them. I bought them about 5 or 6 years ago.

    3. I have and regularly use WD-40 Electrical Contact Cleaner. I can buy it locally and it's less expensive than DeOxit. Works fine.

    4. I have never soldered but want to learn. I am sure there are Youtube instructional videos. Any suggestions on a starter kit?

    So if the problem is the voice coil or spider a recone would fix that? I have watched Youtube videos in the past and reconing looks relatively simple.
     
  14. Beatnik

    Beatnik What's this ?

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    Have you tried simply pushing in on the woofer to see if the coils rubbing ?
     
  15. Mr.White

    Mr.White Super Member

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    I will check that next after I check the diagram to understand what I'm looking for.

    In the meantime......as I stated earlier I have already rotated the speaker inside the cabinet 180 degrees and that had no effect. This was before I switched the drivers and observed that the problem followed the woofer. So I re-cleaned the contacts and made sure the clips were good and tight with a needle nose pliers. I played one CD and it was fine. Immediately following I played another CD [Ricky Nelson - Garden Party MCA CD] and noticed the problem right from the start. No issues playing the previous CD and then wham, the Ricky Nelson CD has the noise right from the first track.

    So, last night I turned the entire speaker upside down and warmed up my receiver for an hour. I turned on the loudness switch and replayed the Ricky Nelson CD at low volume [3:00am] and it played fine all the way through. At times I sat right next to the speaker. No distortion. Nothing but good sound. After this I picked a CD with great dynamics, earth shaking bass and quiet parts here and there. I played my early Japanese pressing of Grand Funk - Survival and that too played great all the way through. Again at low volume with loudness switch on.

    Is there any reason why rotating the speaker 180 degrees in the cabinet made no difference but turning the whole speaker upside down did, at least so far? Ironically the overall sound is better with one speaker upside down. Bass sounds better, lol.
     
  16. Beatnik

    Beatnik What's this ?

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    Could have shifted the magnet or coil just enough when you sat the speaker down to stop rubbing ? I'm no expert, just a thought.

    The 4311's are set up with the woofer up top.

    PS. Every time I read your name I think of Trouble/Manic Frustration.
     

     

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  17. Mr.White

    Mr.White Super Member

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    Ok, since I'm new to this type of diagnosis and it's terminology let me first show you a video;



    I believe what I'm being asked is if what is shown in that video is happening. The answer is no. There is no separation of the cone from the spider. Below is a photo of my woofer sitting normally;

    [​IMG]
     
  18. Mr.White

    Mr.White Super Member

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    Here is a picture of the woofer being pressed downward. You can see those two silver things touching the spider;

    [​IMG]
     
  19. Mr.White

    Mr.White Super Member

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    When I push the cone in and out I do hear a rubbing sound.
     
  20. MCM_Fan

    MCM_Fan AK Subscriber

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    From the photos, it looks like the tinsel lead closest to the camera needs touched up. In its current state, it could be making intermittent contact.
     

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