spamtrap1888 wrote:
On Aug 12, 9:43 am, "Bob F" wrote:
I have a Velodyne F-1800RII that failed. One wire that connects to
the voice coil on the speaker has disconnected. There is a tab on
the tube that the voice coil is wound on where braided cables attach
to the voice coil wire. The braid and connection is then sealed
under what looks like white epoxy. That epoxy separated from the tab
it was one, allowing the braids to move and break their connection
to the voice coil.

Epoxy is used to make rigid connections, not flexible connections. The
cone will flex and the wire should flex with it. The white glue should
be some sort of emulsion.

This really does seem to be epoxy. It is hard and brittle.



To repair the connection, it seems I need to remove the epoxy from
the tab to get to the voice coil wire I need to solder. Does anyone
have any hints on how to proceed, which I imagine means removing the
epoxy?

The glue should just peel off. You could carefully peel it with a
razor knife.

I tried snipping between the two leads, and separated the damaged one. The
covering came off in flying chips. Very brittle stuff. Unfortunately, the voice
coil wire coming out is broken off right where it comes out between the rear
spider and the tube of the voice coil, so I am going to have to separate the
spider from the voice coil tube a bit to repair it. It appears they used the
same glue to glue the spider to the tube.

This speaker is interesting. It has the normal front spider, and another at the
back of the magnet assembly. The two are maybe 5 inches apart.


I've thought about using
my heat gun with a small tube to direct the heat at only the
offending area, but don't know if this would be appropriate.

If I need to carefully cut loose the rear spider from the voice coil
tube to get enough voice coil to solder to, is it likiely that the
coil is a bit below the spider so I won't damage it while cutting
the glue joint between the spider and the tube?

This is more likely to fuch the speaker up royally. I wouldn't try it.

For linearity, the coil should extend well out of the voice coil gap.
Pull up the VC stub, and solder a bit of same gauge magnet wire to it
to where the braid goes in.

You are suggesting that if I can get a hold on the wire, I can just pull a
little loose from the coil to get enough to solder to?

Thanks for your help.