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Thread: JBL LX7 Crossover Restore

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    JBL LX7 Crossover Restore

    How do you open up a sealed LX7 crossover so I can replace the caps?. Thanks

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    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by 2string View Post
    How do you open up a sealed LX7 crossover so I can replace the caps?. Thanks
    How many threads does it take to ask the same question?

    If you have an LX7 crossover, I suppose it'd be easier for you to answer the question—or at least give us a look at the back of the case. Certainly no one who has opened one has seen your last thread, yet, or this one. Maybe you could post a photo for those of us who don't happen to have an LX7 sitting around and then we could all speculate on the how, and perhaps some good might come of it?
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

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    Moderator please delete this topic...Thanks

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    OK I figured out how to open them Pretty simple and I feel stupid. Does anyone restore these?



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    Few ( to zero ) active members have the LX7 network ( & apparently even fewer have ever wanted to crack that model open ).

    That said, that specific era of ( larger networks ) are typically riveted together.

    Once the rivets are drilled out, most of them expose a box full of components that are encased in wax ( though some others might of used tar ).

    The wax can be removed ( others before you have done that successfully ) by using a source of constant heat ( like an oven or large stove-top water-filled boiler ).

    I've seen pics from members where they have successfully replaced the wax ( paraffin wax, I presume ).

    Re-assembly will rely on sheet metal screws ( or rivets, if you own one ).


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    Quote Originally Posted by Earl K View Post
    Few ( to zero ) active members have the LX7 network ( & apparently even fewer have ever wanted to crack that model open ).

    That said, that specific era of ( larger networks ) are typically riveted together.

    Once the rivets are drilled out, most of them expose a box full of components that are encased in wax ( though some others might of used tar ).

    The wax can be removed ( others before you have done that successfully ) by using a source of constant heat ( like an oven or large stove-top water-filled boiler ).

    I've seen pics from members where they have successfully replaced the wax ( paraffin wax, I presume ).

    Re-assembly will rely on sheet metal screws ( or rivets, if you own one ).

    I hadn't looked at them in a long time. It has screws that I didn't see. Very easy to open. Looks like tar and it's very hard.

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    That's any easy one, you should try one that's been filled to the brim!

    Put the potted networks in the freezer for about an hour and the material will chip out fairly easily, done it many times

    Disconnect the wiring from the front cover face and level switch first
    As the potting material warms up to room temperature while you're working on it things will start to get a little messy (the stuff will start to smear and grub up your hands)
    Have some mineral spirits near by and some paper towels

    Just prepare your work area and work smart, it's not as bad as it looks

    Heating is NOT the way to go, yeah it'll work eventually but 10x the work and clean up
    And even in a molten state the stuff will barely pour but for a few seconds and once it's been melted and re-cooled it's an even bigger mess and even more difficult to remove because now it's been reactivated and stuck to warm parts like glue (the factory pour was hot potting material on room temperature parts)

    In other words, don't do this with heat even though that's instictively the way to go

    You will need several tools, a good ice pick, a small sharp chisel and a flat blade screw driver
    Cut gently and hammer lighty, this is not a brute force proposition
    If you make your initial cuts in the right places the stuff will come out in nice big chunks, if you study things carefully and make your strikes in the right spots, the entire assembly will pop out of the box which will make things go much faster

    Once you start to really expose the components you can break off a lot of it with your fingers
    Work slow and carefully and as soon as things start to warm up re-chill the box to keep the tar hard and brittle
    After everything's out and in the open and most of the junk's been removed from the assembly you can do a final cosmetic clean up with a heat gun or hair dryer and some mineral spirits

    As chunks of the material start to pop out, little slivers will fly around, like chipping a block of ice, so do this in a place where you can clean up easily (like don't do it over a white carpet)

    I sit out back on my deck when I do them

    Have fun!

    Joe

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    Quote Originally Posted by Joseph Smith Jr View Post
    That's any easy one, you should try one that's been filled to the brim!

    Put the potted networks in the freezer for about an hour and the material will chip out fairly easily, done it many times

    Disconnect the wiring from the front cover face and level switch first
    As the potting material warms up to room temperature while you're working on it things will start to get a little messy (the stuff will start to smear and grub up your hands)
    Have some mineral spirits near by and some paper towels

    Just prepare your work area and work smart, it's not as bad as it looks

    Heating is NOT the way to go, yeah it'll work eventually but 10x the work and clean up
    And even in a molten state the stuff will barely pour but for a few seconds and once it's been melted and re-cooled it's an even bigger mess and even more difficult to remove because now it's been reactivated and stuck to warm parts like glue (the factory pour was hot potting material on room temperature parts)

    In other words, don't do this with heat even though that's instictively the way to go

    You will need several tools, a good ice pick, a small sharp chisel and a flat blade screw driver
    Cut gently and hammer lighty, this is not a brute force proposition
    If you make your initial cuts in the right places the stuff will come out in nice big chunks, if you study things carefully and make your strikes in the right spots, the entire assembly will pop out of the box which will make things go much faster

    Once you start to really expose the components you can break off a lot of it with your fingers
    Work slow and carefully and as soon as things start to warm up re-chill the box to keep the tar hard and brittle
    After everything's out and in the open and most of the junk's been removed from the assembly you can do a final cosmetic clean up with a heat gun or hair dryer and some mineral spirits

    As chunks of the material start to pop out, little slivers will fly around, like chipping a block of ice, so do this in a place where you can clean up easily (like don't do it over a white carpet)

    I sit out back on my deck when I do them

    Have fun!

    Joe

    Good Stuff ! ( all that )


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    Thanks for the great help. Good to know these things ahead of time. My local repair guy said, if they are working with no issues to leave them alone. He said there's mostly resistors in them. Will I gain any performance by restoring them?

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    Quote Originally Posted by 2string View Post
    Thanks for the great help. Go to know these things ahead of time. My local repair guy said, if they are working with no issues to leave them alone. He said there's mostly resistors in them. Will I gain any performance by restoring them?
    Quote Originally Posted by 2string View Post
    OK is there any way to restore a LX7 crossover?
    Quote Originally Posted by 2string View Post
    52 views and no help!!! I must be on the wrong forum. Can someone direct me to the right place. Thanks
    Quote Originally Posted by 2string View Post
    Moderator please delete this topic...Thanks
    Two threads, and an expression of impatience for not receiving an instantaneous answer over a holiday weekend and now this?

    So, I have to ask, why did you ask the questions in the first place? But yes, I agree, always good to have a plan. It's also good to know what it is you want to do

    Thought you were going to do this work yourself from the way you posed your initial inquiry

    Now it sounds like now you are looking for a reason to not put in the effort as work is involved
    I'm not into the mechanic A says, mechanic B says speculation opinion game, it's a losing one, so I can't offer much help with that

    I know what I would do if they were mine and I had them out and torn down to the point that you have, but that's another story

    Sounds like your local repair guy isn't into it unless it has a zipper or buttons (and most vintage gear doesn't)

    To answer the new question, yes, you will gain performance and especially so if any of the caps have drifted
    For every 4 I change out at least one is off spec enough to make a difference
    Whether it's enough to justify the effort to YOUR ears is a question that I can't answer
    Only you and God know the answer to that one

    Best of luck whatever you decide to, or not to, do

    Joe

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    Quote Originally Posted by Joseph Smith Jr View Post
    Two threads, and an expression of impatience for not receiving an instantaneous answer over a holiday weekend and now this?

    So, I have to ask, why did you ask the questions in the first place? But yes, I agree, always good to have a plan. It's also good to know what it is you want to do

    Thought you were going to do this work yourself from the way you posed your initial inquiry

    Now it sounds like now you are looking for a reason to not put in the effort as work is involved
    I'm not into the mechanic A says, mechanic B says speculation opinion game, it's a losing one, so I can't offer much help with that

    I know what I would do if they were mine and I had them out and torn down to the point that you have, but that's another story

    Sounds like your local repair guy isn't into it unless it has a zipper or buttons (and most vintage gear doesn't)

    To answer the new question, yes, you will gain performance and especially so if any of the caps have drifted
    For every 4 I change out at least one is off spec enough to make a difference
    Whether it's enough to justify the effort to YOUR ears is a question that I can't answer
    Only you and God know the answer to that one

    Best of luck whatever you decide to, or not to, do

    Joe
    The holiday didn't seem to effect the amount of views I had. Anyways Thanks for your help. Just trying to get some advice. Cheers
    Oh you didn't need to add an extra comment. Just answering my question would have been fine.

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    Quote Originally Posted by 2string View Post
    The holiday didn't seem to effect the amount of views I had. Anyways Thanks for your help. Just trying to get some advice. Cheers
    If advice was all you wanted then that is what you should have asked for, in "General Information"
    And maybe, over the Independence Day holiday no one had 20 or 30 minutes they were willing to spend typing to give you specific help and answers to your very specific questions

    Joe

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    Quote Originally Posted by Joseph Smith Jr View Post
    If advice was all you wanted then that is what you should have asked for, in "General Information"
    And maybe, over the Independence Day holiday no one had 20 or 30 minutes they were willing to spend typing to give you specific help and answers to your very specific questions

    Joe
    Yes sir.. I was wrong I should have waited until after the holiday to get advice. My bad...
    edit...3 months a member and you already think you rule the roost! 175 post. You are a busy guy... That averages out to almost 2 post per day.

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    Quote Originally Posted by 2string View Post
    Oh you didn't need to add an extra comment. Just answering my question would have been fine . . .

    Yes sir.. I was wrong I should have waited until after the holiday to get advice. My bad...
    edit...3 months a member and you already think you rule the roost! 175 post. You are a busy guy... That averages out to almost 2 post per day.
    Wagner is operating currently under the alias "Joe Smith". He's been around for years under the name Thomas Wagner. His treatment of you is simply his normal behavior. Probably why he "left" and re-joined with the current alias. Who knows?

    Patience, Tadpole! All in good time.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

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    Quote Originally Posted by BMWCCA View Post
    Wagner is operating currently under the alias "Joe Smith". He's been around for years under the name Thomas Wagner. His treatment of you is simply his normal behavior. Probably why he "left" and re-joined with the current alias. Who knows?

    Patience, Tadpole! All in good time.
    Joe Smith...lol. No problem I can take it. I most likely was a little impatient.

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