035TiA Disassembly

Discussion in 'The Lansing Legacy' started by milo63, Aug 20, 2018.

  1. milo63

    milo63 AK Subscriber Subscriber

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    Or "hold my beer while I break stuff"

    I've got like a dozen of these in various iterations of JBL speakers (4406(2), 4408, L60T. L5, L1) and I'm sure they all have rotten foam. I splurged and bought the fix kit on the interwebs with the idea of reverse-engineering (sorry internet seller, if your price was in line with the perceived value I'd just buy a bunch and be done).

    Exhibit A, my worst (spare) 035 and the repair kit.
    [​IMG]

    That's not good, another seller has O-rings...maybe I'll go for bulk pricing.

    [​IMG]

    [​IMG]

    Flip it over

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    Some gentle prying under the magnet.

    [​IMG]

    Yuck, I just finished scraping surrounds off of a pair of 4408's, pretty sure this is the same stuff. The kit came with two smaller plugs, there's no place for one on the 035 that I can find (I cleaned the residual off, no plug there).

    [​IMG]

    The dome popped put nicely.

    [​IMG]

    A poster on a JBL forum said that he used a 7/8" punch (got that) and some foam he had. I spent a long time at work checking foam properties in various packaging before I found a close imitation.

    [​IMG]

    Once I figure out a way to fairly accurately slice my foam to size I'll punch out a few and get to work. I'm thinking a band saw with a fence, slow and steady.

    This is just the physical part, I need to figure out a frequency sweep to compare before/after for my working speakers to see if I'm wasting my time.

    AK has been an invaluable resource for my projects, this is my way of trying to pay it back.
     
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  2. Zonker92

    Zonker92 All shiny and chrome Subscriber

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    Be super-careful with those tiny leads! I broke them and it was a PITA to fix them. Eventually I gave up.
     
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  3. milo63

    milo63 AK Subscriber Subscriber

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    266
    Location:
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    Just realized I don't need an actual O-ring and ordered ten feet of bulk 1/16" O-ring material.
     
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  4. Stan man

    Stan man Active Member

    Messages:
    425
    Yeah,
    the screen is held magnetically . Very nice. I leave my screen off. It simply sounds less veiled with no screen.
    Keep us posted on your fix.
     
  5. ivandezande

    ivandezande Super Member

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    This post....is just wrong.....
     
  6. Stan man

    Stan man Active Member

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    425
    Are you gonna elaborate?
    What is "just wrong" ? Sir.
     

     

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  7. grey

    grey Well-Known Member

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    I had to sharpen the the 7/8 punch with a fine stone to get decent results. Light twists and tapping over masonite gave me a few good ones and a few duds.

    The smaller plugs go under the center of the dome. You can sharpen a piece of tubing and make more. You will probably find them either under and over the larger plug when you start taking them apart. Some didn't have one or it turned into micro-dust.
     
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  8. grey

    grey Well-Known Member

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    858
    Location:
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    Those push terminals have a death grip. I used a pick to loosen them a bit for removal and re-tensioned them before assembly.
     
  9. Zonker92

    Zonker92 All shiny and chrome Subscriber

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    Good idea. The problem I had arose when I peeled off the face plate; it had some tape or adhesive that tore the leads underneath it. The wires were so small that I literally had trouble seeing them, much less fixing them. (I subsequently found some threads describing promising ways to fix them.)
     
    Last edited: Aug 27, 2018
  10. grey

    grey Well-Known Member

    Messages:
    858
    Location:
    Houston, Tx.
    Ah, I see. I use a plastic putty knife to work the stuck phrams loose and fortunately I've not botched the seal so far. Even being careful, I'm sure it just happens occasionally.

    There is a couple with perfect domes here that have the terminals snapped off. I know it has been done before, but I just can't seem to get interested enough to repair them:no:
     
  11. milo63

    milo63 AK Subscriber Subscriber

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    Weird...I had none and no place to put one unless it just gets glued to the foam. I haven't checked this thread in a few days (on vacation) so I missed that pearl.

    Onward!
     

     

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  12. milo63

    milo63 AK Subscriber Subscriber

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    Using half of the purchased kit I glued the foam to the metal (removed sludge to the left for comparison).

    [​IMG]

    And carefully reassembled with 10" of bulk 1/16 O-ring. (a real O-ring would have worked better and should be cheap once sourced)

    [​IMG]
     
  13. milo63

    milo63 AK Subscriber Subscriber

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    Location:
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    I installed the one refurbed tweeter in an L60t (sans woofer) with an original (assumed bad) tweeter in the other, downloaded a speaker testing tone app and plugged it in to my Technics SA-300 that I can't sell for $50.

    Sweep the frequency and I hear zero difference.
    Play some music and I hear zero notable difference. Some sounds *might* be less harsh but there is no eureka moment.

    Still, the thought of the decomposing foam is enough to press on with the project.

    @grey, your input is much appreciated. So, the harder little plug goes where? I thought there'd be a hole to plug somewhere but there's nothing obvious.
     
  14. milo63

    milo63 AK Subscriber Subscriber

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    It will stay in place magnetically but there's meant to be a O-ring for positive securing.

    If it works for you run with it.
     
  15. Zonker92

    Zonker92 All shiny and chrome Subscriber

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    I think the little plug rests atop the big one, directly under the dome.
     
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  16. grey

    grey Well-Known Member

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    I could hear it when there was a serious issue with the foam. I remember the intro to one of the songs on Floyd's DSOTM having a pronounced, nasty sound.
    Regardless of test results, you're doing the right thing for maintenance. You can imagine that the voice coil will heat up if it is working against foam debris in the gap.

    Between the large plug and the dome is where I've found most of the small plugs.
     
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  17. milo63

    milo63 AK Subscriber Subscriber

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    You are correct, I just got a reply from the seller and I did it wrong.
    Glue/double back tape the little plug to the center and put the larger foam over the top.
    No idea what the function of the little plug is but I'll redo it and report back.
     
  18. Zonker92

    Zonker92 All shiny and chrome Subscriber

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  19. milo63

    milo63 AK Subscriber Subscriber

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    Location:
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    -Bought a $20 bandsaw online to slice my foam in a *hopefully* even slab for my hole punch.
    -Found a denser piece of foam that I'll knock a few 1/4" cores out of to replicate the small bits.

    Electronix is easy!

    Stay tuned...or not.
     
  20. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Can you give us a link for that product?
     

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