#1
Hello,
The school mixer is having issues and I believe them to be from dirty faders.
On a few channels(I was using an MP3 player to test.) When you push the volume up it randomly cuts out and becomes very quiet. If you then quickly push the fader up and down it fixes it, but it goes extremely loud.
I'm guessing this is because of a dirty fader.

Rather than have the music department waste a couple hundred on getting a tech to do it, I figured I'd do it as I am confident in my skills.
I'd rather have them spend it on another amp for the monitors.

Anyways, getting to the point:
I've cleaned pots before but not faders(Technically a fader is a pot.).
I spray in the track with compressed air.
Spray a tiny bit of contact cleaner(pot cleaner) safe for plastic in the track next to the fader knob.
Use a Q-Tip to remove any excess.
Is this correct?
How long do I have to wait before turning the mixer on again?

Thanks for any help. Figured I ask here and be sure I am doing it correctly before working on someones expensive equipment.
--timbit
..I was watching my death.
#2
Contact cleaner and canned air.

Do not use an air compressor as those tend to contain water.

I depending on what I am cleaning, I wait around 10 -15 minutes before powering up again.
#3
I'd have done exactly that, compressed air, contact cleaner etc. Seeing as a fader is just a straight pot i recon it should work fine. Contact cleaner dries pretty quickly so i don't think it should take any time at all.
#4
Quote by CodeMonk
Contact cleaner and canned air.

Do not use an air compressor as those tend to contain water.

I depending on what I am cleaning, I wait around 10 -15 minutes before powering up again.


I don't think I'd be willing to haul my 80 pound air compressor to school on the bus anyways.

Anything you reccomend I do while I have the mixer open?
I was thinking maybe I should put pot cleaner in the Gain pots. There's also noise coming from the Talkback mic input so I'll check that out as well.
..I was watching my death.
#6
Quote by CodeMonk
Clean what looks/sounds dirty I guess?
Don't "fix" what ain't broken.


I figured that much out.
I'm talking about general maintenance. I guess I'll check all the solder joints while in there and tighten up all the pots and jacks.
..I was watching my death.
#8
I just realized,
Could the symptoms that I have already said be directly linked to the amp?
I remember reading somewhere that if the amp was run at the wrong impedance, the amp could be screwed up; pushing the input signal coming out of the mixer could trigger the amp to peak and start working again for a while.
I'll have to do some more troubleshooting tomorrow as I didn't even realize something untill now.
Can anyone clarify on the said amp thing?
--timbit
..I was watching my death.
#9
I'm very sure that it just has dirty pots. If they were paying you for this, it'd be best to get all new pots. The originals will be back to square one in a year or 2.
#10
Quote by Invader Jim
I'm very sure that it just has dirty pots. If they were paying you for this, it'd be best to get all new pots. The originals will be back to square one in a year or 2.

Problem with the school district though,
They definately would not pay someone without a degree in whatever it is, even though I am quite capable of doing it for even 1/8 of the cost of taking it to a tech.

I don't think the teacher is willing to ask for funding on that anyways, he just got $2000 for an Xyplophone but he really bought two Mbox's and two copies of Protools 9(Which I don't like by the way, Cubase is clearly superior.).

Where do I spray the contact cleaner?
I understand that the faders have a helix thing and the knob is just turning that which turns the pot inside.
Do I have to open up the mixer, or can I spray from up top?

I bought some compressed air today, is it supposed to sound like there's liquid inside?
It also says it contains Difluoroethane and that it is toxic. I thought I bought plain compressed air.
..I was watching my death.
#11
I'm pretty sure that the cleaner is indeed liquid inside. It comes out as a gas, though.

Diflouroethane is the actual compressed gas. They say it is air, but they use the diflouroethane because it is easier to compress. It is toxic, but only when concentrated and then inhaled.
#12
Quote by Fuzz93
I'm pretty sure that the cleaner is indeed liquid inside. It comes out as a gas, though.

Diflouroethane is the actual compressed gas. They say it is air, but they use the diflouroethane because it is easier to compress. It is toxic, but only when concentrated and then inhaled.


Thanks for clearing that up.
Now I can rest assured that I will not unintentionally spray liquid into the faders.
..I was watching my death.
#13
I'm still unsure about where to spray the contact cleaner.
Do I just do a spray a small amount near the knob(If anyone has the actual name for this, tell me please.) and just move in around to spread it?
..I was watching my death.
#14
Quote by timbit2006
Thanks for clearing that up.
Now I can rest assured that I will not unintentionally spray liquid into the faders.


I just realised that I forgot to tell you to keep the can upright as you spray, otherwise you may spray liquid.
#15
Quote by Fuzz93
I just realised that I forgot to tell you to keep the can upright as you spray, otherwise you may spray liquid.


I read that somewhere else anyways.
But thanks for telling me this.
..I was watching my death.
#16
I hate modern technology, serious.

The faders have a rubber-like cover on them with a slit so the slider can run along it. It's supposed to help with keeping the faders clean, but really it's more of a pain in the ass.
I had to take the whole mixer apart and I found out that there is one PCB board for all the pots and phaders.
I took the mixer home to work on it, so now it's sitting beside me. Guess I should work on it.
All the knobs are off, and I can see why the faders are so screwed up... Dirt and dust everywhere. I can even see a drop of coffee on there beside one of the auxillary send pots...
I wish people would take care of the school mixer, people just don't respect stuff that isn't their own.
..I was watching my death.
#17
Done.
Mostly anyways. Done the whole cleaning part. Just gotta put in all the screws and wait for the knobs to dry.
It's the first time the mixer has been cleaned since 2001. That was when it was new. I never looked at the board close enough to see how nasty it is. There's ten years of finger grease/dirt/anything on someone's fingers on the knobs.
Anyone have reccomendations to clean knobs?
Currently, I have them soaking in a tupperware cointainer with hot water and dish soap.

EDIT: 100% done. The mixer is working perfectly.
The talkback mic doesn't buzz when activated anymore even though I completely forgot to look at it while it was open. Maybe there was some dust in the pot that I blew out unintentionally.
Anyways, thanks for the help.
..I was watching my death.
Last edited by timbit2006 at Apr 16, 2011,