XLR-PRO needs repair

[Jaime Espiritu]

I think I need a new replacement plug for this unit. I tested the unit on two cameras and this unit doesn't work hearing anything. Is it recommended to replace the plug as a diy project?

[Andrew Dean]

I think I have interpreted your question as:

I have an XLR cable that is no longer functioning. I confirmed the problem was with the cable by connecting it two two different cameras with the same results.

If that is incorrect, I apologize, and could you please provide more information?

And if it is correct, then the next obvious question is:

Did you also connect the same microphone to the two cameras using a different XLR cable, so that you could confirm the problem was not with the microphone or both cameras?

Assuming that it is the cable, you most likely will not need to buy a new connector. There just isnt much to "break" in XLR connectors themselves.

In most cases with a failed XLR cable, the problem is that one of the wires has broken or the solder on the connector has failed. As a DIY project, the first thing you should do is open up both xlr connectors and look to see if any of the wires have come loose and if so, re-solder them. If not, put a ohm-meter between each of the three wires on opposite ends of the cable and see if you have a solid connection. If there is a fault within the wire, you will need to track it down. In my experience the fault is usually within a few inches of each end, so I would generally cut back a few inches of cable on each side, re-strip the wire and solder each wire back one at a time (so its obvious which color goes to where.).

In the event the fault is not on either end, its usually obvious where it is, with a visibly mangled part of the cable somewhere in between.

But check the solder joins first. Its almost always there.

There are several designs to how XLR connectors are held together. Most modern ones you unscrew the tapered "tension relief" portion from the barrel body and the guts slide out. In older switchcraft cables you have little flathead screws that *reverse thread* to hold the tension relief and the guts in place. So you turn those as if you were tightening in order to loosen. weird.

If you cant figure it out, post some photos of the ends or guts and somebody can talk you through it. If you are any good at soldering at all, then repairing XLR cables is quite simple.

cheers!

[Jaime Espiritu]

Thanks. I connected two different XLR cables to a mic. I found out the XLR unit wasn't working because I have an XLR to 1/8" plug. I used that to test a mic and the mic works.

I already opened up the unit's box and the solder joints connecting the wires to the cable is solid.

I'll test each wire to find the break.

Thanks for the advice....

[Brian Drysdale]

XLR connectors are usually robust, chances are the problem may be in the cable close to the connector.

If you've re-soldered the joints in the XLR without success, it's worth cutting off say a foot of the cable and remaking the XLR with the new end of the shortened cable. You can use a solder removal tool to extract the old solder inside the XLR, so you're making fresh joints.

[Pete Cofrancesco]

I'd buy new cable because I wouldn't want to take a chance but sounds like you want a diy project. use a voltmeter to do a continuity check to find out which wire it is.

[Jay West]

Jaime, yes you can fix the plug yourself if that is the problem.

I'm assuming that you are talking one of the XLR-Pro Adapters which were made/sold under the Studio One and Sign Video brands. (For those who don't know, this is a passive two channel mixer for video cameras).

Since you were able to get signals from an XLR mic with an XLR-to-1/8" mini cable adapter, the problem is obviously in the XLR Pro. I'm assuming that you first checked that the unit had not accidentally been switched from "mic" to "line level." (With line level selected, the mic signal is probably not strong enough for you to hear anything from your camera.)

You said you checked the solder fittings. Was that a visual inspection or did you test them with a VOM? If you didn't use a VOM, use one. Small solder connections like these can sometimes fool you but they won't fool the VOM.

Also, you need to use a VOM to check the traces on the circuit board (to make sure there isn't a problem with the circuit board) and also check the continuity from the fittings to the 1/8" mini-stereo plug. If you get continuity inside the box but not to the contact-tips on the end of the plug, then the problem has to be with the plug or its cable. If the problem is inside the box on the little circuit board (unlikely but possible) then you either need very good soldering skills or its time to buy a replacement box. In my case, I'd be more likely to burn holes in the circuit board than I would to repair a wire trace.

Chances are the problem will be right at the end of the cable where it goes into the plug-housing/fitting that plugs into your camera. This is where the cable-wires get the most bending and strain. Since the plug is a molded unit, there is no practical way to cut it open and fix any breaks in the wires in there. You need to replace the connection either by getting a replacement 1/8" mini-stereo plug (from an electronics supply house or a place like Radio Shack) or else by by adapting (i.e., cutting one end off of) a 1/8"mini-stereo patch cable or earphone extension cable. Even large hardware stores and big-box electronics stores carry these kinds of cable, so they might be more readily available to you.

Replacing the plug itself is fussier and requires delicate soldering soldering skills. Patching in a cable might be easier. You can cut one end off a patch cable (the female jack on an earphone cable) and strip leads at the ends of the wires. If you've got soldering skills (and time and a solder iron), you can simply replace the cable connections inside the XLR box. If you are out on the road someplace or don't have suitable soldering skills, you could leave the existing cable in place and try using butt connectors with the patch cable or earphone extension cable. The instructions for my old XLR Pro came with a wiring diagram that showed which wire went to which part of the plug. (If only I could find those isntruction!) If you don't have access to the wiring diagram, you might try calling Sign or Studio One. Alternately, use your VOM on the existing plug and you can probably identify at least two of which wires go to which part of the plug. Chances are that only one of the wires is likely to broken at the plug. If you can get to a Radio Shack or an electronics supply place, you should also get a section of "heat shink" cable covering. You slip this on over the wire, crimp on the butt connectors, slide the heatshrink over the connectors and wire, and apply heat. Heat hair dryer is best, but you can use an open flame from a match. The heat gives you a shrink wrap around the butt-connectors which otherwise would be a very temporary fix. You could also try wrapping the connectors with electrical tape although I would find that messy and troublesome with wires this small.

Let us know how it goes.

[Jaime Espiritu]

Ok...The area is too tight to solder a new cable. I broke a couple of resistors in the meantime. Anyone have a schematic of this SignVideo XLR-PRO unit?

If I can't fix it, I'm going to use my Zoom recorder for the future. I can overlay it on top of my clips. (It sounds better anyway...)