Mixers/Consoles Assignment Buttons (L+R/Group) not always working

[JHWelch]

So I am working with a Crest Audio X-Eight (About 10 years old), running Avenue Q at my college.

I have had several problems with it, often assuming it was a missunderstanding on my part. Last night I realized that many of the switches on the board, specifically those for Left Right and group assignment on the channels simply do not work.

I had 6 mics attached to a drum kit all assigned to a group which was in turn assigned to Left Right. I then noticed that it was only actually coming out Right. If I jammed the assignment button down all the way and wiggled it a bit, I sometimes could get it to come out left as well. When I moved it to another group entirely, that Group's LR assignment button didn't work at all.

Once I realized this, it started to explain a lot of the other problems I have been having (including a mono channel that when not panned would only go to Right)

In my opinion, a 10 year old board with rather light use should not be exhibiting problems like this, are there any quick fixes, I.E. Compressed air, alcohol, repeatedly pushing the button. And what could have caused this in the first place.

Thanks for all the help, I'll be pulling my hair out.

Also, we are in tech and go up Friday, so sending it for service is out of the question.

 

[cpf]

Looks like you've done what I was going to suggest (although real contact cleaner is more effective than alcohol IME). I would take apart the board and see if the switches look replaceable, and if so, do that.

10 years on a board isn't that great, but I had a Crest 44-channel board up and die in 3 years flat, so...

 

[museav]

Just out of curiosity, how are the "LCR" and "PAN ON" switches set for the channels involved? On the subgroups, any chance any of the "REVERSE AUX/GRP" switches are selected? You might want to basically clear the console to make sure there is not some unexpected routing or control applied.

Beyond that, maybe some other "jammed the assignment button down all the way and wiggled it a bit" light use?

 

[JHWelch]

There are no global buttons I don't believe, and I have two identical channels with the buttons pressed the same which are acting differently. I really do think its the buttons.

I have not tried the compressed air yet, but if it is worth a shot I will try it out. How easy is the board to open? Is it worth the risk of pulling on a section?

 

[Benjod82]

Been a few years since we passed ours along, but we ran into the plastic push buttons used for Phantom power, group sends, etc going bad and non longer engaging (even when pressed), only solution we had was to remove modules and send them in for repair.

 

[FMEng]

The cause is oxidation of the switch contacts. Get some Caig DeoxIT D series spray. Open up the console and flush into any and all openings of the switch body. Vigorously exercise the switch immediately after applying the spray. To keep the switches working longer, after cleaning then apply Caig Gold G series. It works as a preservative. Don't worry if excess spray goes all over circuit boards as it is harmless and will evaporate.

Both of these products are highly effective. We had a couple of very expensive radio mixing consoles whose buss assign switches needed their annual DeoxIT bath or they would just quit working. The magic spray kept both consoles working well for 16 years without ever replacing a switch. No switch or connector contact is immune from the effects of pollution and humidity unless it is kept in a vacuum.

DeoxIT is available at most electronic supply houses. In a pinch, Radio Shack stores carry a package of the two together, but the price is a bit high for the quantity. But I have to give Radio Shack props for carrying it and it is probably the most useful item in the whole store.

DeoxIT®, #D5S-6

DeoxIT®/DeoxIT Gold® Spray Twin Pack - RadioShack.com