[morzh]

Question: if I remove the cone from the 20 speaker in order to extract the field coil, do I then when assembling it back need to center the cone and / or the pole, or are those self-centering?

I am asking because obviously it is easier and safe to send just the coil, and they will charge less if they do not have to do assy-disassy.

[Ron Ramirez]

You will have to recenter the voice coil with shims cut from a business card once you reinstall the cone. As for the pole piece itself, that part should be self-centering when you reinstall it.

Remember, for disassembly, remove cone with voice coil first, then remove the pole piece, then remove field coil. To reassemble, set field coil in place, install pole piece, then install cone/voice coil. You probably know this already, but some of our friends reading may not know.

[morzh]

Ron

Every reiteration is helpful.

I hope the cone is not glued under the pieces that hold it to the speaker frame?

[Ron Ramirez]

The cone might be glued to the speaker frame on the outer edge of the cone. I've seen some 20/70/90 speakers that had the outer edge glued to the frame, and some that weren't (or else the glue turned loose over the decades). So, proceed with caution.

[morzh]

What is the good agent to soften the glue and what glue should be used to glue it back?

[Ron Ramirez]

What is the good agent to soften the glue

Acetone.

and what glue should be used to glue it back?

I wouldn't bother gluing it back...the trim ring with the screws is quite sufficient to hold it in place. This will also make it easier to remove the cone or recenter the voice coil, if you ever need to.

[morzh]

OK, a problem.

The central screw holding the spider won't budge.

I punctured the spider when the screwdriver slipped. Twice.
I can fix that, but. Not sure how to proceed.

[Ron Ramirez]

Sounds like a careful application of PB Blaster is in order. Great stuff...smelly, but great.

[morzh]

I do not have it.
What is it, how and where is it applied?
Will it damage the cone - spider if contact occurs?

Is there a tool that does not slip, like a screwdriver with a sleeve?


I think maybe I ship it the way it is - I am only going to ruin it more.
OK, will pay a bit more.

[Warren]

You might know, but ...Did you try another screwdriver? Maybe the next size bigger... sometimes on hard to turn screws you really have to make sure the blade of the screwdriver fits inside the slot of the screw with no extra space at all. Then it grabs alot better and wont slip as easy.

[morzh]

This one did fit. Any bigger one simply will create another bigger hole

[sam]

hey morzh
pb blaster is great I use at work a lot ,can you soak a rag in it and let sit over night works best or use heat torch pen I have dermal tool can make slot larger if it stripes and reverse drill bits if you need them
sam

[Ron Ramirez]

I see...PB Blaster is in a spray can, should be available at any hardware store. I don't know if it will harm the solid spider; I don't think it would, but I would also not want to get the spider soaked with that stuff, either. The problem is that the stuff would probably wick into the spider instead of wicking into the screw threads. ???

[morzh]

Could be.....

But I do recognize my shortcomings when it comes to handling tools and such.....
Maybe paying extra 10 bucks to people who know what they are doing is not such a bad idea after all

[Jamie]

Maybe try heating the screw with your soldering iron? I have never taken one apart, so use this idea at your own risk.