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View Full Version : 2425 - Crud in gap, degraded foam



robertbartsch
11-26-2008, 06:37 AM
Is it typical to find aluminum crud in the voice coil gap? I swaped out the original working diaphragm since it seemed a bit tired. Anyway, can performance be improved just by cleaning out the crud in the gap?

What can I use for the degraded foam on the cap?

Zilch
11-26-2008, 06:11 PM
What can I use for the degraded foam on the cap?The proper replacement part from JBL Pro Parts, if available, might be a start....

SMKSoundPro
11-29-2008, 04:02 PM
Sure. A shattered diaphragm leaves all of its nasty bits of tiny aluminum shards in the gap. Certainly there may be some magnetic material that has mysteriously found its way there.

Remove old diaphragm.
Blow out gap with compressed air until clean.
Use masking tape and "digger" (business card stock) to wipe the tape around the gap to retreive any magnetic bits of crap until perfectly clean.
CAUTION: Do not drop compression driver on foot! (That is a whole nother forum group!)
Install new diaphragm carefully.
Do not twist the phragm in the gap like a bottle cap.
Install three stainless steel 6-32 screws and tighten the diaphragm very gently. Do not over torque.
Re-connect the leads.
Fold lead wires carefully into place.
Replace back cap and secure with stainless steel screws.
Sweep on a signal generator to assure no rubbing or buzzing.
Replace driver on horn (if necessary).
Enjoy your favorite sounding speaker cabinets.
Marvel at the incredible sound a new diaphragm makes.
Tell your friends and family you accomplished this maintenance task yourself, hoping for an 'atta boy in return, (that you will never receive.)
Then point and laugh at their bose crap!
"What, you gonna hurt me with that little thing?"
Oh Please, Mary!

Keep it simple!
Scotty.

SMKSoundPro
11-29-2008, 04:10 PM
Is it typical to find aluminum crud in the voice coil gap? I swaped out the original working diaphragm since it seemed a bit tired. Anyway, can performance be improved just by cleaning out the crud in the gap?

What can I use for the degraded foam on the cap?

YES.

robertbartsch
12-02-2008, 09:06 AM
OK - I followed the procedures for diagragm replacement exactly - including using compressed air. I'm using OEM diaphragms.

The results are amazing! I'm running the rebuilt unit without any foam on the cover, however.

...my next swap project involves some 075 bullet tweeters. Obviously, these have (1) alignment pins, and (2) soldered leads which differ from the design of the 2425.

Are there any special cosiderations for the 075 diaphragm swap?

Thx...

Robh3606
12-02-2008, 09:25 AM
Are there any special cosiderations for the 075 diaphragm swap?


Yes, whatever you do don't twist the diaphram when you tighten the bulit nose. Make sure it does not turn at all when you reinstall it. Just carefully tighten the screw.

Rob:)