This is a socapex brand multiconnector. Commonly used in the theatrical and concert tour industry to carry multiple power circuits to lights and other equipment. One of the common failure modes of this connector is what we call a spinner. That's when the pins are no longer locked into place in relationship to the alignment key in the connector. As you can imagine, it can spin around and mate with the other connector, but now circuit one is now coming out on circuit six's wires, or something else. This would be bad.
As you look at the picture with the alignment pin visible, you can see that it is adjacent to pin number seven, it is supposed to be halfway between pins six and seven. If you take the backshell off the connector you will find that you can freely spin the disk that all the pins are coming through inside the metal shell.
Danger! This repair should not be undertaken by someone unfamiliar with repairing theatrical electrical equipment. If you do this wrong, you can start fires, destroy equipment, and kill people when the misrepaired cable is put back into service. If you have not replaced these connectors already, this repair is probably beyond your level of skills. Don't do it, leave it to a professional repair shop to do it.
We can replace the entire connector, but the connector is not cheap, and may not be available from your local theater lighting dealer off the shelf. So, this is a solution that repairs the connector with materials available from any well stocked hardware store or big box home center.
You will need:
Screwdrivers and small needle nose pliers.
two part epoxy. (J.B. WELD five minute works well for me)
a #6 socket head set screw about 3/8 inch long
Matching hex wrench for the screw.
Step 1: Take Apart the Connector
I forgot to take pictures of taking the connector apart. Sorry about that. Disconnect all sources of power. Lockout tagout if this is a connector on a dimmer or built in patch cables in a building.
Before starting, inspect the connector. If you have burned, bent or broken pins or sockets, then these also need to be replaced. These can be individually replaced, but that is probably only doable with a well stocked repair shop, as there are a couple of different generations of connector and the pins and sockets are incompatible.
Screw the connector into the mating connector on the other end of the cable. Don't worry if the pins are not correctly lined up, you just want it mated to a known good connector. This keeps the outer rotating screw part pulled all the way down while you are working on it. If that slips up, it is a PITA to put it back together without breaking the little grounding spring between them. This also gives you proper alignment when you are putting things back together.
Remove the backshell of the connector. Don't lose any of the parts, you will need them all to put it back together. I use old medication bottles to hold all the little screws and bits so they don't get lost. You can also take the opportunity to repaint the backshell, it is looking a bit battered, isn't it. Inspect the backshell for cracks or broken off bits of metal. Replace as needed. Inspect the wires where they are soldered or crimped to the pins or sockets. Any broken wires, signs of arcing and sparking, open solder joints also need to be fixed, and may force you to an entire new connector anyway.
Reach inside the connector with a small pair of needle nosed pliers and
you will see a circular steel retaining ring with a little tab sticking out. Just carefully pull that out of the little slot. This frees up the contact disk which can now easily be removed by pulling gently on the cable. Look for the place the alignment nub on the disk has been broken off. It is halfway between pins one and twelve. (opposite from the connector alignment nub mentioned earlier.
Take a marker and mark the spot where the nub got broken off. Now, using a round needle file, file a notch into the disk. This notch is where the replacement alignment screw is going to go. Take your time with this, remove some material, put it back into the shell and try sliding the new screw in. Ideally you will have a tight fit that you have to actually screw it into place, and there is no wiggle of the screw or the contact disk. Caution, the fine dust produced by the filing of the plastic is obnoxious, don't breathe it in.
Step 2: Glue in the Screw and Reassemble.
Now put the connector disk and the cable back into the plug, making sure it is seated all the way down. Take the circular retaining ring and put it back into it's little slot. Once you have pushed the contacts all the way down you should be able to have it snap back into place. Rotate the retaining ring so the gap is over the notch you just filed.
Mix up some epoxy. I have had good luck with J.B. Weld, get the five minute working time stuff. using a toothpick, mix it up, and then smear a little bit of it into the notch you just created. Take the screw and give the threads a coating. Screw the thing into the notch until it bottoms out. Now wait about twenty minutes for the epoxy to set up and gain some strength. The epoxy is just to keep the metal screw from coming out and shorting things out inside the connector.
Now put the backshell back on and you are done. Give it a couple hours of rest if you can for the epoxy to gain full strength.
COngratulations. all done. Test it before you put it into service to make sure you didn't do something stupid like filing the notch on the wrong side.
Step 3: Replacing Burned Pins or Sockets.
If you are running a repair shop, you can save the broken bits of dead connectors as organ donors for other connectors. To replace a burned pin, unsolder the bad pin or socket. This may require unsoldering other wires to get at it. You can now carefully pull apart the two plastic disks that make up the contact disk.
Take the pin or socket you just removed. Go through your collection of good pins or sockets and find the one that is the exact match. There are different generations of connector and they are subtly different, and incompatible. Put the pin in and solder all the wires back to their appropriate contacts.