Howdy...

I'd purchased a project 2 stack, (FH-1, MB-2, MF1-X), and then one of the 1504-4 woofers went out.
I pulled it, and noted that the cone was frozen.
Hmmmm!

Another gentle push revealled that it was frozen to a point, then would break free and move... but seemed 'dampened'.
Not what I expected from a high compliance woofer of course.

So, disassembly ensued, and what I found was a trail of black tar-like goo on the inside of the former, and within the VC gap.

So "what's the goo?" I thought... it's a sealed folded horn... the plywood inside is as untouched as the day it left the factory.

I realized that it is most likely the decayed foam weather stripping used to seal the doghouse hatch.

*If the vented pole piece contained foam, it could also be from there. Although the goo I see around the pole piece I suspect was melted as it was sucked in.

I was able to get the goo off of the former inside using MEK, but how to get the stuff out of the pole piece will be a trick.
Short of pouring MEK in there (and I don't want to breathe in any more of those fumes... they are bad for you kids...), there appears to be no option (e.g. for disassembly of the pole piece).

Q-tips work somewhat, but cannot get fully into the crevaces and must be disassembled before they fit well. I've considered dipping a 3x5 card in MEK and running it through the gap... but then we have that hazardous fume thing again.

Any suggestions mechanically, or for another type of solvent or ?

Will try to get a pic up shortly...

thanks!

Yes, it was indeed the foam vent screen. This type of foam will eventually disintegrate. I once had a couple of thousands of dollasr worth of Nikon lenses that were ruined, as I kept them in a case in an attic for several years.

You can try soaking the entire magnet structure in some solvent. Then clean out the gap. I had the same thing happen to one of my PR-1 studio monitors. The other one still works, but I'm sure it will develop the same problem eventurally, since they are more than 12 years old.

Thanks for the confirmation Marty.

Geez, I wonder how many years these played with it in place.
What was surprising is that there seems to be no deformation of the VC former.
Seems impossible that it would've functioned without ripping itself to shreds, or at least warping.
(goo was primarily in one streak, we assume where gravity took the foam bits or where it melted down into).

It's occurred to me that Acetone may work. Will have to pick some up...

Acetone will do fine, just be sure to use that in a well ventilated space and get the foam out completely, Ive had this issue with some DTH Concert subs, Disassemble and use a cue tip and the Acetone and youll get it out, DO NOT APPLY ACETONE to the VOICE COIL ANYWHERE, it will releases the varnish and youll have a far stickier problem. Keep the Acetone away from the VOICE COIL itself, ok to use on the magnet and metal components. You can use a small pic to scrape out the residue but be careful and dont scrape the magnet etc too hard.

_________________
Don Lanier
Pearl Pro Audio
http://www.pearlproaudio.com
Facebook.com/Pearl Pro Audio

Thanks for the advice Don.

Here's a pic of one half-way cleaned.
Used MEK afterall, but it needs to soak into the goo... I just dampened a swatch of cloth with it and sat it on there for a while.

Make sure you check for "powder" lodged between the dust cap and cone!

Scott

Just keep these solvents away from the Voice coil or any other GLUED pieces as they will loosen and dissolve the Glue/Varnish weaking the speaker....MEK....Ive had my hands in that before, It has a BURNING feeling if you get it on your skin....nasty volatile stuff but will remove darn near anything....Acetone is safer but just as flammable and the fumes can be strong if used Indoor....always be careful with anything Like this and allow lots of air circulation....

_________________
Don Lanier
Pearl Pro Audio
http://www.pearlproaudio.com
Facebook.com/Pearl Pro Audio

Thanks all for the advice. They're both working well now. I ended up just using MEK after all.
Sanded and resealed the doghouse doors with new weather stripping as well.

*Also modified the typo in the original post '1505' to the proper '1504'. Ooops.