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Discussion Starter #1
I have a damaged 12W7 damaged from a dry rotted surround finally failing and damaging the VC in the process. I also have someone that is going to give me a seemingly perfect 12W7 that just doesn't play. I haven't seen it yet, but I am told that it moves freely, doesn't bind or crunch when pushed, yet just doesn't produce any sound. I asked if it was tested with a voltmeter, I am thinking (or hoping more like) that maybe it's just a bad tinsel lead.

I am going to pick that one up tomorrow, am told that other than the fact that it is not producing sound, it is flawless and recent, maybe good for parts?.. Not in my possession just of yet.. I would like to take them apart, just don't know how.. If it is something simple, I'd like to try. If not, I'll take the pair to a local repair and maybe get 1 from the pair.. That would be nice considering JL wants $400 to rebuild just 1.. That includes shipping.. But I live 10 minutes away, wish I could just drop them off.. But they don't want to see my pretty face.. I understand.. It's a business, if they allowed every broke ass Buster with Champagne taste like me into their facility, it could be Mayhem..

Any ideas?
 

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Discussion Starter #3

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Discussion Starter #5
plasma cutter?

lol

Jeremy
That about sums it up!! The epoxy they use on the spider is impenetrable!!

I am going to bite the bullet and have 2 rebuilt, sell the other 2 (2 function, 2 do not, 2 is all I need!!)

For my purposes, these are hands down the best subs I have ever used.. Perfect balance of fast, brute, impacting force, yet detailed enough to blend nicely with my 3 way active front stage for a superb SQ experience, and that's with just decent drivers on my front stage ( A combination of Polk, Boston Pros and Mmats Pro Audio, all soon to be replaced by HAT L8, L4, L1V2)

At full bore (set to kill mode) I have cellar deep bottom end, a rock solid foundation from 28HZ to 63HZ, very tight, linear, forceful impact (I have the sub section that you begin to feel about 10 seconds before I arrive) yet when tuned for SQ, is as subtle and untraceable as many of the SQ subs out there..

In short, I wanted a dual purpose, all around system that affords plenty of cellar deep SPL with very nice SQ when balanced out/blended with front stage.. Still tweaking but the JL's are the foundation I needed to get me there..

DIYMA ROCKS!!
 

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Interesting in selling any of the non working ones? I have a locked up 12W7 that I am still hoping to do something with myself. Finally got it to move a bit by pushing on the spider, but not much...
 

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Discussion Starter #7
Interesting in selling any of the non working ones? I have a locked up 12W7 that I am still hoping to do something with myself. Finally got it to move a bit by pushing on the spider, but not much...
That is a positive indication that the VC is damaged. If you somehow manage to get the spider off without damaging it (virtually impossible) you may get lucky and be able to rewind the VC, that is if the cylinder it is wrapped around isn't crushed.

If you look at the side of the motor, you can actually see part of the VC through a Vent. This may give you an indication of how severe the damage is. The fact that you can't get the cone to move is already and indication that you have serious problems..

I write this knowing that it is more than likely a lost cause, but one never knows, you may get lucky.. The VC winding is thick enough that if you do manage to take it apart in a way that doesn't destroy the spider, you might get lucky and repair the VC. Highly doubtful but worth a looksee considering the fact that JL completely rebuilds them when you send them in for repair. Everything from gets replaced EG: Cone, VC, Spider, plastic parts, surround etc.. Plus the copper winding is so thick that if you manage to get at it by using a plasma cutter to get through the Epoxy that they use to secure the spider, you could possibly rewind it.. It looks to be at minimum a 14 Gage 16 Gage thickness (copper winding is so thick you could possibly rewind it by hand)

In all likelihood, you will need to send it in. But from what I understand, they reuse only the basket and magnet, everything else gets replaced. So go ahead and give it your worst, or best, it's all the same to them should you decide to have it rebuilt after you've mangled it even further ;)
 

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Ha ha well actually thats how I got it to move. The coil looks perfect, even measures fine on the voltmeter and has sound output, just no movement. I took a thin piece of plastic and pushed through the holes in the side and it seemed to "free" the coil up a tiny bit.
 

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Discussion Starter #9
You'd be surprised at how far up you need to push that cone to see the entire VC. It is spec'd @ 29 MM Xmax for good reason!!!!

I had to push mine so far up that the spider was shaped like a cone just to see the damage at the very bottom of the VC, it is very long. I have one with a torn surround that caused the damage to the VC, the other is fine in terms of movement, looks brand new, reads fine. But when you tap the cone, you hear the bottom few windings jingling in there, they have come loose.. Both subs still "play" but they need rebuilding nonetheless..

Trust me, unless there is foreign debris in there causing the "binding" you've definitely got a few loose windings at the very bottom that have caused the seizure.. It will still read normal on a MM as the copper is still there, just that it is probably no longer wound around the bottom. Either way, unless your extremely lucky, it will need to come apart and be rebuilt.

(I've had the same wishful thinking for some time now) GL!
 

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Alright, you have inspired me to try it. I let some fingernail polish remover sit on the glue yesterday, no luck eating it. Going to try Acetone next...
 

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Discussion Starter #11
Alright, you have inspired me to try it. I let some fingernail polish remover sit on the glue yesterday, no luck eating it. Going to try Acetone next...
Someone suggested a Plasma cutter, that sounds about right!!
 

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Well I really don't want to cut the spider if I don't have to. That is my last resort though if I can't get anything to tackle the adhesive. Either that or just get a Boston G5 12" at this point.
 

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Well, ended up cutting the spider. Could not get through that glue for anything. Didn't matter though, the magnet was shifted, causing the coil to "pinch" and burn. Either way, it would have needed rebuilt anyways. Which brings me to my next project... hopefully a writeup of sorts is coming soon...
 

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Well, I am in contact right now trying to get a new voice coil and spider. My fingers are crossed that things will work out and that this won't become a huge paper weight. Right now this is the progress:

 
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