BHGA
06-07-2011, 02:24 PM
I have apair of JBL 240Ti. One day one of the LE41H-1 woofers where stuck!. There was sound but no movement. I could push in the cone using allot of force, and it wery slowly came out again. No voicecoil rubbing sound at all. Strange. Took out the unit and, yes it was stucked, and nothing wrong to see.:confused: To bad, the cone had to come out. I managed to loosen the diagphrame from the foamedge by hand. Then I used som aceton on the spiderglue and so with a screwdriver I carefully got the spider loose. Then some desoldering and so I slowly forced the cone out. I saw the typical JBL white hand writing at the diagphrame said year -85.
Ahh-then I saw it. At the inner end of the magnetventing hole, there was glued a pad of foam over the hole. Proably to stop dirt to enter the magnetic gap. The foam was rottened and pieces had fallen into the magnetic gap and acted like glue in there. No wonder the voicecoil didn’t move. JBL- why did you use that crap foam matrial?:banghead:
Then I cleaned the alu voicecoilform inside carefullywith aceton. Checked and cleaned the magnetic gap as good as possible. Tried the cone in the frame agin and it feels ok. No glued feeling.:D
Now I have two challenges:
1: When will the same happen to the other woofer? I have to take away the foam before it falls apart. How? :dont-know:
2. I have done refoaming but not reconing. I have the sentering ring for the LE14 from a friend. But I don’t know how to remove the orginal JBL black glue that holds the dustcap. Aceton is not softening thatblack glue. Yes, I am reading about carefully knife cutting and new dustcaps,but is there no way to loosen that black glue?
If I find a good way to take of the dustcap I probably have solved nr.1 challenge.
Regards BA
Ahh-then I saw it. At the inner end of the magnetventing hole, there was glued a pad of foam over the hole. Proably to stop dirt to enter the magnetic gap. The foam was rottened and pieces had fallen into the magnetic gap and acted like glue in there. No wonder the voicecoil didn’t move. JBL- why did you use that crap foam matrial?:banghead:
Then I cleaned the alu voicecoilform inside carefullywith aceton. Checked and cleaned the magnetic gap as good as possible. Tried the cone in the frame agin and it feels ok. No glued feeling.:D
Now I have two challenges:
1: When will the same happen to the other woofer? I have to take away the foam before it falls apart. How? :dont-know:
2. I have done refoaming but not reconing. I have the sentering ring for the LE14 from a friend. But I don’t know how to remove the orginal JBL black glue that holds the dustcap. Aceton is not softening thatblack glue. Yes, I am reading about carefully knife cutting and new dustcaps,but is there no way to loosen that black glue?
If I find a good way to take of the dustcap I probably have solved nr.1 challenge.
Regards BA