JBL L100 - need advice for rewiring

[SalonMusique]

Hey everyone, first post here! I am slowly discovering the audiophile world since 2 years. Taking my time to learn bits from here and there. I am very glad I found this forum so much ressources and enthusiasms!

So, I found a nice pair of JBL L100 century (very late model) a week ago. Manage to get them for 200€. They seem to be in a decent state soundwise and esthetically. The cabinet are a bit scratched sadly but nothing terrible. But, as often, the twitter surrounding foam was rotten. After finding some replacement ones online I proceed by peeling off the ones installed without reading further instructions online. To my great despair, I just realised today that I did a stupid mistake and pulled out one of the wires below the glue... I now did some research and found online various post warning about this matter. Honestly I do feel very stupid since I have no particular experience in restoring speakers. So hence my question, is it complicated to rewire the twitter properly or should I get helped from a professional? I don't mind learning and putting some work into it, but sadly I did not found much helping information about this specific situation.

You can find below some picture of the issue.

Thanks in advance for the help!

SalonMusique

 

[SalonMusique]

little update: a tiny part of the copper wire is still sticking out, seems hard to imagine welding this for me but is it possible maybe?

 

[Chris Brown]

No reason no to try. It's just about getting the signal from point A to point B. As a bonus, even if your work is somewhat sloppy, it will be covered up by the new foam. I would compare the DCR (DC Resistance), measured via a multimeter, between both tweeters after your repair to get an idea of how well the repair went.

 

[turnitup]

The foam you are attempting to replace has no real impact on the tweeter, other than to insulate it from the speaker grill (honestly, mostly cosmetic). Resoldering the wire should get you back to a working start again, just take your time and use steady hands. Congratulations on your purchase, you seemingly got a good deal on those. Fun speakers.

Read up on replacing the crossover capacitors on those as well, it should improve their sound dramatically. This is a somewhat difficult task with the L-100s as you have to remove the decal on the front in order to access the crossover. Definitely do your research before attempting further repairs. These are rather valuable speakers to be “experimentally learning on”. Best of luck on your journey, and welcome to AK!

 

[allsmith]

Scrape the wire at the end where you will solder with a razor blade really good and all the way around..it has varnish on it i think, even if not always super clean copper nice and shiny new looking before soldering..Try to just get a small blob of solder on the end of the wire first using good flux core solder or solder paste..Remove just one strand of copper wire from a scrap piece of speaker wire and do the same procedure on the end..Once you have a small blob of solder on the replacement wire just hold the two ends together and then touch with the solder gun and they will solder together nicely..A set of helping hands and a magnifying glass really helps..then just solder to the post

 

[goodolpg]

Would the OP need to use a precaution to prevent too much solder gun heat going where it shouldn't? A heat sink of sorts.
Like a clip on alligator type clip?
Worded that poorly but maybe it will make sense. Could be for different soldering procedure I've read about.

I agree, a magnifying lens might be helpful depending on OP's eyes and vision.
Obviously care must be taken to not let the hot tip touch or go through places it shouldn't.

 

[turnitup]

Scrape the wire at the end where you will solder with a razor blade really good and all the way around..it has varnish on it i think, even if not always super clean copper nice and shiny new looking before soldering..Try to just get a small blob of solder on the end of the wire first using good flux core solder or solder paste..Remove just one strand of copper wire from a scrap piece of speaker wire and do the same procedure on the end..Once you have a small blob of solder on the replacement wire just hold the two ends together and then touch with the solder gun and they will solder together nicely..A set of helping hands and a magnifying glass really helps..then just solder to the post

Just a word of caution, it will be exceedingly easy to scrape the wire and accidentally sever it. It’s extremely delicate, treat it with care. One mishap and it may no longer be repairable…

 

[SalonMusique]

Thank everyone for the warm welcome and the advices! I have a friend working at the CERN coming to help this week, hopefully it will work fine. Just to be sure the outer membrane of the twitter is fragile and will burn instantly if the burning tip of the iron gun touches it? I like the idea of the solder paste but I am afraid it will melt over the membrane. I guess the paste becomes real hot as well right?

 

[Catmanboo]

Would the OP need to use a precaution to prevent too much solder gun heat going where it shouldn't? A heat sink of sorts.
Like a clip on alligator type clip?
Worded that poorly but maybe it will make sense. Could be for different soldering procedure I've read about.

I agree, a magnifying lens might be helpful depending on OP's eyes and vision.
Obviously care must be taken to not let the hot tip touch or go through places it shouldn't.

There's not enough exposed wire to heatsink, plus this is absolutely not a job for a soldering gun. This calls for the smallest iron & tip available, like a 25 watt with a small cone tip.Work this fine will be a touch & done process- if done properly, shouldn't be a chance of overheat damage. Process as described in post 5 above.
OP: this is a 1-shot fix, but use something not as sharp as a razor blade to scrape that tiny stub remaining on the tweeter. Otherwise you risk amputating it-then you're screwed.