Alnico magnets , demagnetize !
Hi jblwolf
Sharp blows to alnico magnets ( such as hammer blows ) are known to demagnetize these magnets. The result is a noticable drop in output level in the top end & sometimes an overall drop across the whole spectrum . Then a remag is a must. That's part of the price of having JBL do the job. I'd strongly caution you against trying to break the magnetic pot apart on your own. You are likely to demagnetize the core and worse, hurt yourself at the same time. While it's true the structure is held together mostly by magnetic force , that force is strong enough to crush the ends of a finger ( or much worse according to my reconer ) when you try to pry that top plate off ( you're really playing with fire here ).
Leave this size job to pro reconers ( preferrably someone over 50 who's done this enough to know the risks - there are a few oldtimers who might do this job - they'll likely advise that a remag is order after their work is done )
regards <. Earl K
You can have the work done for $90
I contacted my local pro shop for a similar repair. They couldn't do it themselves but referred me to Orange County Speaker. This is where they send their own drivers for repair. Here is there web site http://www.speakerrepair.com/ocsrepairprice.html
According to both shops the original throats are difficult to obtain, and my local shope told me that they can no longer obtain 2441 diaphragms from Northridge, so buy them while you can. Jammin Jersey is still advertising them for $150. Mike Caldwell at vintageaudiosales.com has clean used 2440 domes for $150 as well.
The procedure for replacing the throat involves degaussing the driver, replacing the throat, reassembling and regaussing. The cost for this was $65. The cost for realigning the phase plug, which apparently uses a special press and shims, was $35. A large cost is going to be shipping. Orange County is a JBL authorized repair shop and the quote is a lot less than JBL's quote.
Tim