David Nebenzahl wrote in message
.com...
n cook spake thus:
David Nebenzahl wrote in message
.com...
n cook spake thus:
Or admiration of the art of louspeaker making. 46V DC on 8 ohm 10
inch speaker, didn't last long, going o/c. Decided to try
rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid
connections.
Heating the frame with a hot air gun and pushing the periphery of
the cone with a well used and rounded wooden kitchen spatula,
separated cleanly from the gummy glue. Put in spacers to stretch
the inner dust diaphragm and hot air gun heating unglued the
periphery of that corrugated disc. I didn't expect to see what
was inside. A burnt mass of wire and the innermost end of the
penetrating lacquered paper cylinder neatly burnt off in a
perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick
and 2 layers of about 2 x 30 turns of 6 thou wire (originally). I
don't fancy trying to rewind on a small paper cylinder and fixing
to the remnant all with such XY&Z precision to clear that 2x
25thou slot gap in the magnet.
Possibly impertinent question: wouldn't a guy want to use a mandrel
of some kind to wind the coil on? That way you wouldn't have to
worry about a flimsy paper cylinder collapsing, no? (Like maybe a
turned piece of wood.)
But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I
only
come across a coil/cylinder rubbing in the magnet housing after abuse.
OK, then how about lacquering the assembly after winding; shouldn't this
help it keep its shape? I think this is what speaker mfrs. do.
--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.
- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists
I've been doing some measuring and looks as though such speakers use a sort
of air bearing/ ground effect.
Inside diameter of the slot in the magnet something a bit less than 1.502 in
so probably 1.5 inches. Inside diameter of the paper cylinder that goes
inside the magnet gap about 1.65 inches so with a gap width of bit greater
than 66 thou and paper plus double thickness coil of 15 thou means the wire
cannot touch the outer diameter of the magnet gap. And I just cannot believe
that in all operational circumstances that the inside of the paper cylinder
can never touch the inside surface of the slot with only 7 thou of
clearance. A silicone treatment to the inside surface of the paper cylinder
would make sense, anyone know whether it is used ?
Knowing that I might have a go gluing a new bit of cylinder and new coil to
the existing remnant of cylinder as there is plenty of external room for
excess glue/binding.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/