08-28-2009, 04:45 PM
First of all, try connecting another p.m. speaker to the secondary of the output transformer and see if the set works. Consider any test speaker you use expendible.
The repair of the connection between the tiny wire from the voice coil to the lug on the frame is a delicate one. If you can get the glue or varnish off the 'spot' where the tiny wires come out of the voice coil on the cone, you can see if the voice coil still has continuity. I would try a tiny amount of acetone or nail polish remover on a small spotting brush, and do blot it very well. If this doesn't work, and you have a delicate hand and a sharp scalpel you could try to remove whatever is there to expose the metal. You can't burn it off, because remember, it's sitting on a piece of paper that is very very old.
Once you have determined that all is well, and the voice coil is not rubbing, you will prevail.
You will have to procure a small length of wire similar to what is on he other side. I have used bits and pieces of old phono cartridge shield wire, must have been decades ago in a similar rescue mission. Somebody on this forum probably has a roll of it and will step up and send you few inches of it, which will be a lifetime supply.
Anyway, once you have an exposed clean contact area, the most delicate of soldering jobs must be done to attach the wire to the spot on the cone. Tin the wire first, and make the connection quickly. Reinforce the immediate area around your join with the glue of your choice, and allow it to cure thouroughly. You then punch a small hole through the cone (away from the tiny wire from the voice coil, using a pin and gently enlarge it to accomidate the wire, feed the wire back to the terminal on the frame of the speaker, leave a little slack (look on the good side to estimate how much) so it can traverse the spectrum of the sound it should reproduce, and solder the other end. Finished!
There are as many ways to repair a cone as there are remedies for the common cold. Everything from toilet paper and elmer's glue to silicone putty, to rubber cement. What you want in the end is something that moves freely, is properly centered to avoid rubbing and buzzing, and works. Every tear, missing piece, and hole should be addressed to make this happen.
If you want inner beauty as well, and the set is otherwise OK, you can get the speaker re-coned. The experts who do this can take care of all this.
I have a similar set awaiting a dial plate, and the speaker was a basket case as well. It had all sorts of paper tape and glue all over it, and I reversed most of it. Looks like H**l, but plays pretty good.
Have fun. Now we'll hear from people who know much more about this stuff than I do, with even better suggestions
The repair of the connection between the tiny wire from the voice coil to the lug on the frame is a delicate one. If you can get the glue or varnish off the 'spot' where the tiny wires come out of the voice coil on the cone, you can see if the voice coil still has continuity. I would try a tiny amount of acetone or nail polish remover on a small spotting brush, and do blot it very well. If this doesn't work, and you have a delicate hand and a sharp scalpel you could try to remove whatever is there to expose the metal. You can't burn it off, because remember, it's sitting on a piece of paper that is very very old.
Once you have determined that all is well, and the voice coil is not rubbing, you will prevail.
You will have to procure a small length of wire similar to what is on he other side. I have used bits and pieces of old phono cartridge shield wire, must have been decades ago in a similar rescue mission. Somebody on this forum probably has a roll of it and will step up and send you few inches of it, which will be a lifetime supply.
Anyway, once you have an exposed clean contact area, the most delicate of soldering jobs must be done to attach the wire to the spot on the cone. Tin the wire first, and make the connection quickly. Reinforce the immediate area around your join with the glue of your choice, and allow it to cure thouroughly. You then punch a small hole through the cone (away from the tiny wire from the voice coil, using a pin and gently enlarge it to accomidate the wire, feed the wire back to the terminal on the frame of the speaker, leave a little slack (look on the good side to estimate how much) so it can traverse the spectrum of the sound it should reproduce, and solder the other end. Finished!
There are as many ways to repair a cone as there are remedies for the common cold. Everything from toilet paper and elmer's glue to silicone putty, to rubber cement. What you want in the end is something that moves freely, is properly centered to avoid rubbing and buzzing, and works. Every tear, missing piece, and hole should be addressed to make this happen.
If you want inner beauty as well, and the set is otherwise OK, you can get the speaker re-coned. The experts who do this can take care of all this.
I have a similar set awaiting a dial plate, and the speaker was a basket case as well. It had all sorts of paper tape and glue all over it, and I reversed most of it. Looks like H**l, but plays pretty good.
Have fun. Now we'll hear from people who know much more about this stuff than I do, with even better suggestions
