damaged diaphragm

[EE99]

Do you have any idea what caused this?
The coil on the Diaphragm is damaged due to mechanical wear.

73634

The lid on the driver (2450) was missing one of the screws so it may not have been completely sealed.
It is possible that the pressure from the 12" woofer in the same box affected the diaphragm ?

Should have a gig tomorrow so it's really bad timing that it would break right now.
Hoping to mount a B & C driver temporarily.

[Ed Zeppeli]

I can't see the pressure in the cabinet being responsible. It looks like the diaphragm was installed incorrectly and/or migrated in the gap somehow. Do those 'phragms have centering pins?

Warren

[1audiohack]

If the coil isn't open or shorted, keeping the coil out of contact with the top plate should keep it working.

No pins but the bottom does center in a recess. Sometimes the foil hangs out of the plastic a bit and it takes a bit of work with a file to allow some wiggle room when mounting and centering the coil. A fairly low frequemcy buzz test (200-300Hz) at a level sufficient to move the coil is needed to assure there is no coil contact. With the eight screws just snug enough to not rattle you can push the top of the diaphragm assembly around by the top plastic ring and make it buzz and not buzz, make it not buzz and tighten it down.

Barry.

[EE99]

OK, I did not know you had to center when mounted.
The coil is open, so I have to buy new diaphragm and mount according to the "no buzz" method
Thanks for the tip

Can you recommend any web shop to order original JBL parts?
Or if some one on here have a pair fore sale.

/Henrik