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JBL L80T Project -- Gone Wrong

Zonker92

Zonker92

All shiny and chrome
Dammit. I Just finished my L80T restoration project, which included recapped L80T3 crossovers, cabinet cleanup, one new midrange and two new tweeters (after I destroyed the first two by opening them up).

I had refoamed both 127H-1 woofers and used shims to get the voice coils aligned, but both before and after the refoam I could hear something touching inside the voice coil gap on one when I moved the cone in and out. I think maybe there's a foreign object in there but I can't get it out. The "friction sound" was so quiet I thought maybe it would not be a problem.

Wrong. I hooked up the speakers, fired them up, only to find one woofer makes a loud rasping noise with bass notes.

Refoaming it (aligning the surround) won't help. I already tried that with shims and the interference was present before and after. It's either a deformed or damaged voice coil or there's a foreign object in there. Any other ideas? Can I remove the entire cone, clean out the gap and replace it, or access it from behind somehow?

Maybe I'll post a WTB for a woofer in BT. Problem is, I had to use larger dust caps as part of the refoam, so it won't match unless I replace the dust cap.

:sigh:

Before the new tweeters:

DSC_2963-1_zpsf094449d.jpg
 
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I'd cut the dustcap off and use a compressor to blow out the gap or slide a piece of double sided tape in the gap. Shine a bright light in the gap to see if you can see anything where the rubbing noise is. I once left a shim in the gap, so I know what you're going through
 
Thanks, Brad and DT. Probably the best plan. The thing that pisses me off is that I could hear something in there while I had the dustcap off, and I tried everything I could think of to get it out, but I forgot to try compressed air and didn't think of a flashlight. Instead, I just poked around in there with some Post-Its and got nowhere. I kept thinking maybe the object was on the outside of the VC, where I had no access. Maybe I should just get in there and try again.
 
Man, those L80t's have been giving you fits it seems.

I've never done JBL woofers yet, but I've had great success using a 30hz test tone rather than shims. When I need to do my L80t woofers, I'll be using the 30hz tone for sure. It seems you have a different issue though. Maybe compressed air will do the trick.
 
Well yeah, good chance it is the outside and you'll have to do surgery, but no alternative to getting in there again, right?
 
Yeah, seems like whenever I buy speakers that need a lot of work, no matter how cheaply I get them, I spend more than they're ever going to be worth, getting them nice again. I just never learn.

DT, as I see my alternatives, I can: (1) tear this woofer apart (or at least remove the dust cap) and try to clean out the VC; (2) Buy at least one used woofer (I'd want to match the larger dust cap, though); or (3) get this one reconed.

(3) is too expensive. (2) is possible and probably my best recourse. (1) may not work, but I see no harm in trying it before trying (2).

So I guess I'll start with (1).

DT, if the crap is on the outside, do you think it would be possible for me to remove the spider and reattach it? Any suggestions there?

Thanks!
 
Can you force the cone forward anough to get it clear of the VC gap? some speakers you can. That might allow you to get whatever crap is in there out.
 
Not sure, but it might be worth a try. (I kind of tried that when I was refoaming them and the surround was off, but it didn't seem to want to come out that far.)
 
It might be bubbled up/cooked varnish on the VC itself, so you'd have to get the VC out of the gap to see. And that'd be the best way to really clean the gap, but you'd need to get the spider off the frame.
 
Zonker92 said:
DT, if the crap is on the outside, do you think it would be possible for me to remove the spider and reattach it? Any suggestions there?
Click to expand...
Your odds are not great without a new spider on-hand, but you can certainly try. I'd have to see a pic to have any idea what to suggest as the first step. Well, I guess obviously if you can work a knife under the adhesive on the outer diameter of the spider, just do that, but you probably can't :).
 
Any spider I've ever messed with (not trying to safely remove one, just messing with ruined speakers) is glued on so strong, I can't see getting one cleanly off the frame. Good news though, the woofer is pretty much shot as is, since it's making noise, that you don't have much to lose.

I see the woofers fairly often on ebay, so if you have to...
 
Yup; nothing to lose at this point ... I found a few threads that say adhesive remover might work on the spider's glue ...
 
I tried removing a spider once, it didn't end up well. It refused to come off, so I just ended up ripping it off, and reconing.

I understand your dilemma.
 
Where are you in CA?

I have a 127H-1 with a broken basket that could be used for parts, I guess.
 
Yup; thanks. But what the hell, at worst I'll just get a new woofer or two. It's only money. :sigh:
 
I reapaired a couple Snell 8" woofers once by cutting the lower edge of the spider, closest to the frame, then putting it all back together with small a bead of glue holding the seam back in place, all around the spider. I used "Goop" let it set up for several day and believe it or no it worked perfectly fine! I did sim the voice coil gap on re-assembly. Seem the glue edge of the Snell spider was put on with a spider eating glue that let go 7~8 years later. I glued the spiders edge back to the metal frame with a controlled bead of Goop- and now I can throw power to it like it was new!
DC
 
OK; thanks! I think I'll cut off the dust cap, try a light and some compressed air; maybe some tape, and if that yields nothing I'll remove the outer edge of the new surround and try to pop it out of the gap. If that fails I'll try some adhesive remover on the edge of the spider. If THAT fails, I may cut off the spider, but I hope it doesn't come to that!

Much appreciated!
 
You can also look into cutting the spider-to-former junction, which sometimes you can do by cutting just slightly into the paper, leaving paper-to-paper for your new glue joint. You'd have to make a small cut into the VC at one point to slip the coil through that hole, but I think it might be better than cutting around the outside above the adhesive.
 
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