Problem with XLR mike connector on mixer

Riaan-Combrink

Some advice guys.

Last week the strangest thing happened to me during a gig. I did the first song. No problem. First song by my partner (who obviously uses a separate microphone plugged into a different mic-in on my mixer), after one verse the vocal goes dead quiet. No sound. Nada.

I stopped the backtrack and gave a sheepish "we're gonna take a short break" :-[. Quick diagnostic on stage. My mic into her cable. No sound. Eliminate mic as problem. Her cable into my mic connection. Full sound. Eliminate cable as problem. My cable and mic into her mic connection. No sound. Diagnosis = something wrong with that channel on the mixer. Plugged her mic and cable into spare channel, and everything perfect. Diagnosis confirmed. 8)

Next night, set up as per normal just to check properly what happened. Plugged her stuff into the original (faulty) channel. Do pre-sound PFL, and notice that I get a full PFL signal (i.e. LED active with amp off) on that channel as with my own mic-channel. Turned amp on, and voila, full sound on the (faulty) channel. Test one-two, etc - everything perfect!! Gig starts, partner sings one verse and *poof* - no sound again. Switch to spare channel and on we go.

Does this make sense to anyone? I know nothing about mixer mechanics. My one has mic preamps on all mic channels. Could something have "blown"? Could this be why I still get PFL-signal but no sound (or at least only temporary sound)? Also, why would it be fine if I test it but go dead when she sings on it? Could the XLR "pot" (for lack of a better word) be damaged or faulty?

I've checked all the obvious stuff on that channel (i.e. gain not accidently turned off, main mix button activated, etc).

Any ideas???

This is the mixer I have:
http://www.behringer.com/EN/Products/UB1832FX.aspx

PS: Leave the "Behringer is @#$%^&&*(()** "what do you expect"?? and be CONSTRUCTIVE!!!!! ? ? It's what I've got at the moment, and I have to live with it :-[

AlanRatcliffe

Intermittent problems are the worst. Usually it's a component or solder joint that is faulty, but only fails when it heats up during use. Only a matter of time before it dies completely, but until then can make it difficult for a tech to track down.

Get it fixed/serviced. A good tech will have ways of forcing a suspect faulty part to fail from putting a signal through it until it fails to spraying a freeze spray on each suspected bit until one of them fails. They can also do some preventative stuff like cleaning and resoldering (dry joints are often the culprits), which can help avoid other channel strips dying at inconvenient moments.

If PFL is working when the channel strip is dead (I know you don't say it is, but it's a good way to isolate half of the strip as the problem) then the mic premp itself (including the trim -the XLR pot you mention) is alright, and the problem is in the EQ or fader section of the strip. Also plugging into the line in or insert on the strip can isolate the preamp as the problem (or not).

One thing I know from bitter experience is that once one strip dies, it's usually only a matter of time until other strips start dying too. We usually do what you have done and use the others and repeat when another dies, until we start running out of strips, when we finally cart it in for a service.

I hate unreliable gear! Usually when a desk reaches the point where bits are dying, I'll fix it and sell it on and get something I can rely on. Sure, it may last a dozen more years with maintenance and the odd repair, but what happens if the next bit to die is in the master section - that kills the gig completely (and how many of us can afford to carry spare desk around?).

Gearhead

Do you need to use that particular channel, having 17 others?