JBL 4312 driver harden up.

[jameswei]

One of the driver (woofer) on my JBL 4312 if really hard, not moving much and caused voice coil rub. Is there a cure? Will a refoam help? The color also turn brown.

 

[janikphoto]

This does not sound good. Remove all the foam (since it's bad, anyway), place the speaker on its back, and try to gently move the cone with your hand. If the speaker still feels like it's hard to move, then you have a voice coil issue, not a surround issue.

 

[Jeffery]

This does not sound good. Remove all the foam (since it's bad, anyway),.

If it has a foam surround, is it a 4312? :scratch2:

 

[janikphoto]

If it has a foam surround, is it a 4312? :scratch2:

he mentioned the surround, and I didn't even think about the model having accordion vs foam... either way, I think it's the voice coil, so he'll probably need a re-coning.

 

[halo71]

Isn't this a common happening of those drivers with age? Seems like I read somewhere of people using brake fluid to soften the surrounds?!?

 

[Vintagegeek]

Is it possible that the magnet has shifted? Maybe the spider has lifted? Pull the driver and do a thorough inspection.

 

[Jeffery]

Isn't this a common happening of those drivers with age? Seems like I read somewhere of people using brake fluid to soften the surrounds?!?

That's for the old white Lansaloy surrounds, not the accordians.

 

[jameswei]

Here's some pictures. One is good.

 

[Bigyank]

One of the driver (woofer) on my JBL 4312 if really hard, not moving much and caused voice coil rub. Is there a cure? Will a refoam help? The color also turn brown.

IMO, the cure is to start looking at either an aftermarket recone or replacement 2213H's.:tears:

Lansing Heritage site is an awesome site to use for JBL research.

 

[janikphoto]

Is it possible that the magnet has shifted? Maybe the spider has lifted? Pull the driver and do a thorough inspection.

I had an old JBL with a shifted magnet and it froze up the whole assembly where it felt like the voice coil was glued in place!