How F'd is my Soundcraft?

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mechanic
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How F'd is my Soundcraft?

Post by mechanic » Mon Oct 23, 2006 4:17 pm

I know someone here knows what this issue is... but kinda hard to describe.

I have a Soundcraft K1 16 channel.

Often the right channel on my mix buss will 'go out'... almost as if there is a 'blockage'... if I crank up some gain and throw the balance all the way to the right, the 'blockage' will 'clear'... there will be a 'pop' and sound will resume flowing to my right channel. When the sound goes out, it is for the whole desk, but I can 'pop' any particular channel (needs to be audio going through it).

this is only in the mix buss, and can happen with any channel... the sound to the direct out won't be affected, but the mix buss (which I monitor with) will go out often enough to be irritating... additionaly, the 'fix' is to crank up the gain on that channel, which obvioulsy you can't do in the middle of the take...

Does this make any sense?

Is it just a matter of cleaning things?

Do I need to pay alot of $ to get a tech to come in?


thanks!

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Post by idylldon » Mon Oct 23, 2006 4:25 pm

Could be many things, but my money's on an intermittent connection somewhere in the 2-buss area. It could be a cold solder joint that's finally causing problems, a bad connection between IC pins and the socket (if they're socketed or a bad solder joint on one of the pins if they're not), a troublesome pot, etc. I have actually seen an IC plugged into a socket that had one of the pins bent up when it was installed at the factory, so it was just "rubbing" against the socket connection instead of being firmly in it. It usually made a connection, but every once in a while it would "disconnect" and cause a problem similar to what you're describing.

Cheers,
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Post by Professor » Mon Oct 23, 2006 4:53 pm

Intermittant connections sound like a good possibility, but the fix you have doesn't seem to fit.
If you leave all the levels the same and just run without the right channel will the signal eventually pop back into place? Or does it instead stay out indefinitely until deliver the jump start.
Also you said that the fix can happen on any channel. Do you mean that you can pop individual channels in & out, or do you mean that any channel can reactivate the entire bus?
I can't remember all the details of the K1. I don't seem to recall any VCA channels on the board, but are there mute groups on it?
If the problem also has a way to 'fix itself' over time then it sounds like a physical connection. But if the only way to cure it is with your method, then it sounds like some kind of relay, VCA, or something like that may have gone out. Maybe a more familiar tech could say, 'oh that's an electrolytic capacitor that is on it's way out, and really does build up a 'blockage' that can be cured by enough juice pushing it back open and restoring the proper charge'. That sounds really fun as an idea, but it's really just complete conjecture, but it may be something on that side of things.
Conveniently the K1 is modular enough that you should be able to pull the master section and double check all those piles of ribbon connectors and such inside.

Oh, you know, I just thought of this - does the failure happen only at the main outputs? Meaning, when it fails, have you listened to any extra outputs like parallel main outs, 2-track sends, headphone outs, all the even busses, etc.? I suppose it could be further down stream than the actual busses. Also try feeding something into a 2-channel return to see if it passes through the master section unharmed.

-Jeremy

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Post by patternagainstuser » Mon Oct 23, 2006 6:12 pm

my soundcraft 200B does that too, but not the mix buss.. just individual channels. i have to turn the gain all the way up real quick and it pops back in to action. weird..

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Post by idylldon » Mon Oct 23, 2006 7:34 pm

Professor wrote:Intermittant connections sound like a good possibility, but the fix you have doesn't seem to fit.
I've seen intermittent connections operate in just this manner. That IC problem I mentioned in my first post was one such instance, and I've also seen it with cold solder joints. The "pop" usually heard might just very well be a microscopic electrical arc, which temporarily restores the marginal connection or it breaks through the oxidation that was preventing a clean signal path.

I've also seen this problem with jumpers between boards; that is, a connection between a mother and daughter board that has been flexed enough to go intermittent.

BTW, if you "rap" on the desk a bit, does it fix itself? This is one way to see if it's a loose connection of some sort.

Cheers,
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Don

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Post by Scodiddly » Mon Oct 23, 2006 7:46 pm

One thing to try is to look for insert jacks on the main outs - exercise them by plugging/unplugging a few times. Often the normalling connection in insert jacks gets dirty over time, needs a little exercise to wipe off the crud/oxides.

Another thing to try is "percussive maintenance" - lift it up a couple inches and let it drop back down. Maybe help with other intermittent connections. Oddly enough I think that equipment that's moved often (live sound equipment) tends not to have these sorts of problems.

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Post by brianroth » Tue Oct 24, 2006 2:21 am

Amen Sco...

I often find these sorts of problems by "whacking" the top of the desk with the side of my fist <g>.

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Post by mechanic » Tue Oct 24, 2006 6:49 pm

hmm... I haven't checked the other busses when it goes out, just the mix and the direct outs (and most importantly, the direct outs are fine). I should definitely get over my fear of opening the thing up and poking around, I _am_ a technical person...

...will also try giving it a good smack. I did take this board from a life on the road, maybe it just misses the abuse.

thanks.

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Post by mr. nick » Thu Oct 26, 2006 12:12 pm

i would start with cleaning and working the master fader, you may have some funk build up. next i would resolder all of the joints on the pcb for the master section, then i would use a cleaner and work the main insert jacks (if that board has them), while you have the board apart make sure all of the ribbon cables are seated and connected securely. lastly, recap the master section. it is all pretty easy stuff, just take your time, have good light and a comfortable work are. good luck!

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Post by getreel » Thu Oct 26, 2006 2:19 pm

I used to have problems with Mackies like that. it was the ribbon cables. we'd reseat them and the problem would disappear for awhile, come back 4 months later, re-seat again...New ribbons on those Mackies were a fix but I'm not sure about Soundcraft stuff. If construction techniques are the same, maybe that. Could be any of the stuff others mentioned too.

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it was a dirty insert jack

Post by mechanic » Wed Jul 31, 2013 10:27 am

... I still lurk on this forum all the time, but I haven't actually logged in in a very long time.


I just logged in today, and figured that after 7 years, I'd post an update :)

It was a dirty insert jack.... Scodiddly nailed it on the head.

It took MANY iterations of contact cleaner and exercising the jack to get it to behave.


It's amazing what tearing apart a mixer completely and cleaning everything can do!

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Post by ashcat_lt » Wed Jul 31, 2013 7:07 pm

My Ghost has that problem too, but I think it's in several places. They are pretty infamous for having the normalled connection at the headphone jack cause something like this.

I was actually running it with an insert cable stuck in each buss insert jack and using a loose module from a patchbay to couple the two TS plugs together. That worked most of the time, but sometimes it would still go out, and I'd have to jack in and out of the phones jack a couple of times.

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Post by Brian » Thu Aug 08, 2013 7:17 pm

ALL analog Soundcrafts that get used where people breathe need regular cleaning.

That is all.
Harumph!

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