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View Full Version : New Dust Cap for D130F Woofer



fecooper
05-26-2009, 10:54 AM
I removed my 40 year old D130F woofer from my cabinet and found that my aluminum dust cap is quite crinkled and I think it may be what's causing some upper mid-frequency harshness I've been hearing. Other than the dented and crinkled dust cap, the speaker is in great condition. Does it make sense to take the speaker to a service center and just have the dust cap replaced or should I go ahead and get the speaker completely re-coned?

Loren42
05-26-2009, 11:57 AM
Just replace the dust cap if everything else is fine.

I forget the exact procedure, but you just need some glue remover (acetone?) to get the old one off and then glue on a new one.

Use a piece of masking tape (the blue painter's tape works good) to act as a handle by attaching just a small edge of the tape to the center of the dome. Do this gently.

Put a small bead of glue around the old ring where the cap was and then lower the dome into place.

There is probably something on this site to help you do it.

BMWCCA
05-26-2009, 12:08 PM
I forget the exact procedure, but you just need some glue remover (acetone?) to get the old one off and then glue on a new one.
I don't know since I've never done one, but I believe I read that the aluminum dome on the extended-range JBLs like the D130, D120, and their F-series counterparts actually had a mechanical connection to the VC/motor in some way. I'm sure there are many here who can tell you for sure (Harvey being one!) but I wouldn't take any drastic steps until you find out for sure. :confused:


Apologies if I'm wrong, but better safe than sorry. My D130s are all as old as I am but their parts are in much better shape!

Edit: In fact the literature on the D130 here (http://www.lansingheritage.org/html/jbl/specs/home-comp/home-comp.htm) speaks about an aluminum "diaphragm" permanently attached to the aluminum voice coil tube.

Tim Rinkerman
05-28-2009, 11:29 AM
It just says it's permanently attached to the voice coil tube...like every other center cap..you'd have a heck of a time centering the voice coil in the gap if you couldn't put shims in it, let alone see it...
Getting the old dome off isn't for a first timer. You have to X-acto it out, using very careful pressure so as not to distort the coil, and, keep a piece of sticky tape under where the knife goes through so you don't drop cutting fragments into the gap. If you get through that succesfully, you want the new one to fit snugly and evenly where the old one was, and run glue in AFTER the dome is in place.
Patience and care are key here.....

spkrman57
05-28-2009, 01:03 PM
Getting the old dome off isn't for a first timer. You have to X-acto it out, using very careful pressure so as not to distort the coil, and, keep a piece of sticky tape under where the knife goes through so you don't drop cutting fragments into the gap.



The magnetic field will draw magnetic tools into the gap with great force if you get close enough!!!

Regards, Ron

fecooper
05-28-2009, 02:10 PM
You all have convinced me to pay someone else to do it. The folks at Speakerex in Tampa Florida have quoted me a very reasonable price - less than $20 per speaker to replace dust cap. When I visit my mother-in-law in Florida, this will be a nice side trip. Thanks for the help.