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Blown woofers-what up with these???


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7 replies to this topic

#1 of 8 OFFLINE   DorianBryant

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Posted February 09 2005 - 04:21 AM

I picked up two pr. of JBL 940's. One pr. is mint. The other pr. has one speaker with the 8" and 10" woofers not working.

Both drivers move in and out without any VC rub or friction. When I try to power the speakers-nothing happens. No movement or sound. No apparent damage.

What might the problem be? Could the VC be fried and still no friction?

To replace them both is too much $-about $180 for both and they are not high quality drivers. I could rebuild them but i have yet to find the kits...

Any thoughts?

#2 of 8 OFFLINE   DorianBryant

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Posted February 09 2005 - 06:55 AM

I am assuming the voice coil has been heated to the point it is now "open." Anyone have any idea of where to get a recoming kit?

PE just has the re-foaming kits from what i have seen. These may not be popular enough to have kits on hand...

#3 of 8 OFFLINE   stephanX

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Posted February 09 2005 - 08:02 AM

If you can find the parameters for the replacements, im sure partsexpress has something with similar enough parameters
Can your 450$(cad) sub hit 120db at 40hz?

#4 of 8 OFFLINE   Allen Ross

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Posted February 09 2005 - 10:11 AM

open them up and whip out your DMM
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#5 of 8 OFFLINE   Brian Bunge

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Posted February 09 2005 - 01:20 PM

Yeah, also open them up and make sure that nothing has been disconnected. I've seen it happen more than once.
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#6 of 8 OFFLINE   John E Janowitz

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Posted February 09 2005 - 05:06 PM

yep, more likely that a component in the crossover has an issue than the VC. I've seen that a lot of times.

John

#7 of 8 OFFLINE   DorianBryant

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Posted February 09 2005 - 09:12 PM

I have both drivers out. I swapped them in with the other speaker, ran a signal straight to the driver, and the 9 volt battery test. With power straight to the leads on the speaker, its it dead, no movement at all. No friction and no movement...

#8 of 8 OFFLINE   Wayne A. Pflughaupt

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Posted February 10 2005 - 09:16 AM

Open VC for sure.

If you want to get them up and running again, your best bet is to get some service replacements from JBL.

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