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[Stephen Swaffer]

We have been having trouble with noise in multiple locations on an A&H GL3800.  I have posted before-someone suggested exercising/cleaning insert jacks.  I have done this, with no noticeable improvement.  I have localized,at least on some channels, the problem to the XLR input jacks and plan to replace most of those very soon.

This Sunday we began having trouble with the pulpit mic and tried the obvious fixes mid service.  Changed out mics, cables and exercised input connector.  The odd thing is, when soloing the mic, or listening to main or monitor mix on headphones the noise was never heard-I was listening to headphones while another tech listened to the service live and cued me when the mic "broke up."  This caused me, during a convenient moment to try exercising the output connectors-though line level shouldn't be as susceptible to noise, should it?   The problem seemed to improve after all this-but never completely went away.

It seems odd to me that I could not hear the trouble on the phones-perhaps a ribbon connector,which I can and will try to clean-but the problem also seemed localized to the specific mic/channel.  We used other mics and line inputs throughout the service and some for extended periods of time,but never had static except on the one mic/channel.

Given the recent weather changes/increased humidity I am all but 100% certain it is a connection issue.  I have a lot of experience troubleshooting complex systems though, and it troubles me that observations contradict each other as I try to localize the problem-what am I missing?

[Bob Leonard]

How old is the system, and how long has it been in place.

[Stephen Swaffer]

Approximately 7 years

[Tim Perry]

Approximately 7 years

Try spraying the jacks with contact cleaner. I suggest Deoxit D-5

[Bob Leonard]

Try spraying the jacks with contact cleaner. I suggest Deoxit D-5

Absolutely. Either give the board a full and complete cleaning or take it somewhere were it can be done for you by a competent and trained technician.

[Stephen Swaffer]

That's pretty much the conclusion I have come to-I don't like "shotgun" repairs-but it seems that is on order here.  I am certainly not looking for a silver bullet with this post-and maybe I am overlooking something in my observation.  Was more puzzled by not hearing noise that appears to be localized to one channel in the phones when listening to the main "out" and what I could learn from understanding that anomaly for future reference.  I had always assumed that the phones should be an honest representation of the output-obviously at some point there are connections beyond the tap for the phones, but that should affect everything?

[David Parker]

That's pretty much the conclusion I have come to-I don't like "shotgun" repairs-but it seems that is on order here.  I am certainly not looking for a silver bullet with this post-and maybe I am overlooking something in my observation.  Was more puzzled by not hearing noise that appears to be localized to one channel in the phones when listening to the main "out" and what I could learn from understanding that anomaly for future reference.  I had always assumed that the phones should be an honest representation of the output-obviously at some point there are connections beyond the tap for the phones, but that should affect everything?

two suggestions. XLR connectors are not standard. Some are different sizes, and this will cause intermittent problems. The name brand ones will never give you problems, it's the no-name counterfeits
second, it sounds like it's a switch somewhere in the signal chain. Switches that divert the signal to a submaster or something. I had trouble with an A&H mixer, the switch that changed the submaster faders to aux send. Had to use a pointed tool of some sort to work the switch, because it was recessed. Had to be exercised routinely.

[Mike Pyle]

It could be caused by the channel insert jack losing the normal connection. Try running a 1/4" plug in& out of that connector a few times with some de-oxit applied.

[ProSoundWeb Community]