AR-3 Mid Repair

[Guest]

Hello AR Peoples

I have a pair of 3's. One of the mids very tiny wires has broken off under the mesh. I removed the mesh and there is about a half inch of it to work with.Can someone give advice on a tiny wire connecter or a method of adding a longer wire to it. The mid itself works great when its connected so I think its worth saving,Im just scared to break it off any more.

Thanks

Brian O

mbkpao@yahoo.com

[tysontom]

Re-attaching the aluminum lead-wire connection on an AR-3 is tough business, but with patience you can do it. If the dome is still working well, it is definitely well worth the effort to fix it.

In the AR-3, the voice coil itself terminates out of the gap area in the form of two lead wires that are curved in a semi-circular fashion up and out of the dome area, and then laid down flat on top of electrical tape on the blued-steel top plate. Black electrical tape is placed on top of the two wires, and they then proceed out to the tweeter terminal plate. Later versions had copper wire (easier to solder) soldered to the aluminum pigtails, and then the copper lead-out was soldered to the terminal plate. Most AR-3's had aluminum wire, which is very difficult to solder with anything but Alumisol aluminum solder, and even that can be difficult. Stress breaks with the aluminum wire were not uncommon.

If you carefully peel back the black tape, you will have access to more of the lead wire, but be very careful not to break the wire in another place. Since you have approximately one-half inch of leadwire to work with, you can take a pair of small needle-nose pliers, or tweezers, and carefully form a tiny "loop" in the wire from the dome end, and try to work the other broken end into that loop and tie them together, very carefully, and crimp the union. You must be very patient. Then try to solder the loop with aluminum solder if you can locate any. If you have a good mechanical connection, you might be able to make the solder connection work with standard solder, but this does not always work, and you can have a cold-solder connection pretty easily. With a good mechanical crimp, most of the work will be done by the crimp anyway, and the solder will be secondary. Be certain to have electrical tape under the wire, and when finished, over the wire up to about 1/2-inch or 3/4-inch distance from the dome breakout point.

If you do not have enough aluminum wire to work with, you can go to the tweeter terminal strip, heat one of the connectors with a soldering gun, and with tweezers (this is where you need your third hand), unwrap a short section of aluminum wire and piece that in for the repair, using the loop method I mentioned above. There is usually a half-inch or so of extra wire wrapped around the terminal strip, and this should help if necessary.

I hope you have steady hands.

--Tom Tyson

[Guest]

Tom,

Thankyou for your knowledgeable and detailed response, I will attempt this,but I will first try to locate some aluminum solder and some aluminum wire. Any suggestions where to look?

Also winding copper wire to the aluminum lead will not work?

Thanks

Brian Oneill

mbkpao@yahoo.com

[tysontom]

You can try using copper wire to join to the aluminum. The best way to get a small strand of copper wire is to take a small piece of standed wire and unravel the strands until you get a single, small strand. You could make the loops with it just as with the aluminum wire. Make sure you have a small, but strong physical connection before soldering. Usually, regular solder doesn't do well with aluminum, and you will end up with a cold-solder joint, but if you have the good physical connection, you should be okay.

As far as sourcing aluminum solder and aluminum wire, I think you can get the aluminum solder "Alumisol" from places like Neward Electronics, etc. I have no idea where you could get the aluminum wire in such small sizes. But if you unravel some of the wire at the tweeter terminal post, you should have enough for a repair.

--Tom Tyson

[tysontom]

Make that: "Newark Electronics," not Neward.

--Tom Tyson