One of the things that sucks the most with mixers is shitty faders. Now I'm no expert, but in my experience, it is usually due to a build up of crap (dust) on the tracks the fader runs on. If you have a reasonably new model, you can just buy replacement parts.
If your like me, and have a discontinued model, trying to find a replacement is a pain in the ass.
I choose to save some money and clean them myself.
It may be that not all faders are the same, but they 'probably' work on the same lines (as I have said b4 I'm no tech).
This is the process...

First, you need to desolder the fader from the board, using a solder sucker.



Next, remove the lugs that hold the fader case to the board. This one has 6 (the folded over bits, just use small pliers)



Gently pull the board away from the case...



Pull out the centre sliding peice that the knob fits on to.



This shot shows the gunk that has bulit up on the connections...



The track the connections run along...



Using an old toothbrush, clean along the strips. There are probably better ways of doing this, like isoprpyl aclohol etc, but I don't have any handy to me. This seems to work ok anyway.



Next, clean the connections of the slider part, just be careful not to damage them as some I have seen are quite delicate. These may also need to be 'bent out' a little to make a stronger contact with the track.



Once done, put it back together and fold the lugs back over.



Your then ready to resolder and re assemble.




Hopefully this will fix your dodgy mixer. If not don't blame me, it's probably a more serious issue. if so and you need a new fader, it won't hurt trying this procedure first anyway. It only took me about 30mins start to finish.

One thing to be careful of is the way the board fits to the chasis. In this case one side had a larger cutout in the board which meant it could only go one way. however when doing this with my pitch slider on the 1200, the board can go either way, and the clider track is slightly different in that one side of centre has 2 tracks, and the other has 3. I have no idea of the importance of this difference (maybe someone else can chip in here), but best to keep it the same.

awesome cleaning guide thanks mate!

I have had reel good luck with the Caig line of products. I've used Deoxit to bring some scratchy pots back to life. I also used it on my 1200's pitch faders to keep them working good. I use the cleaner than follow up with the lube. There products are also good preventative maintenance to keep your faders and pots it top shape. I bought mine at GC.

http://www.caig.com/

allen

Appreciated!!
Say skot_e, you wouldn't have to have any decent technique to lively up my pio cdj's pitchfader?? It wanders around from 0,05 to 0,15, like it's resonating or somethin?

Sorry dude i'm not familiar with CDJ's (I've never even played on one, but I do want one. need $$$ 4 that).
I would pressume they may be digital rather than analogue, but I'm not sure.
If they're not under warranty, and you really wanna fix them, be prepared to buy a replacement, and then just rip em out and pull em appart to take a look. You might be able to do a repair, and if not you've not lost anthing coz you were going to replace it anyway.
After all, thats how I learned.

Famous last words; I do know a little about electricity