Mixtrack Pro 3 volume fader issues

I’m not sure if this is a bug or not. I’ve been using an older beta of Mixxx (2.1.0-beta1 I think) with my Mixtrack Pro 3 for about two or three years. It’s had random glitches here or there, but no real problems. On Saturday everything was working fine. I went to use it on Monday and the right volume fader would phyiscally move but it didn’t translate into Mixxx. I tried it in Serato DJ Lite with the same issue. I brushed out the fader path several times with a soft, clean paint brush; blasted it with compressed air, and cleaned the contacts with rubbing alcohol. Best I could get was about 50% travel down in Mixxx.

Thinking this is clearly a hardware issue, tonight I fired off a message to Numark. After that, I figured I’d give it one last shot and tried it in Serato. Full volume range, of course.

So I decided to upgrade to the current version of Mixxx, thinking now this is a Beta issue but the problem still exists. By using the Learning mode under the controller profile, I was able to get Mixxx to re-learn the volume control to an extent - but I’m still getting about 15 to 25% volume in Mixxx. To bring it down to 0% I have to use the mouse for the last little bit.

Has anyone come across this before? I’m not so sure this is hardware anymore, but why would Mixxx “forget” this one thing? All other features appear to work fine.

The least I can recommend to investigate the issue is:
start mixxx from the terminal with --controllerDebug parameter. As the name suggests, this will print a lot of controller debug messages to the terminal, most importantly: all Midi messages sent by the controller.
When you move the Vol fader only, check if it sends values from 0 (off) to 127 (full volume).
If this is the case please come back and we probably can figure a way to fix this.

( if it does send 0 and 127 there may be some intermediate values missing and it might be softTakeover “protecting” you from rapidly jumping values. This is relevant only if you use the two controller decks to control 4 decks in Mixxx, or if you use mouse and controller concurrently for the Mixxx mixer (how would do that?).)

If the same issue happens in Serato, then yes it is a hardware problem. IME cheap controllers start to develop these issues after ~2-3 years of use. You could try DeoxIT Fader Lube.

I can also recommend TUNER 600 spray (if you’re located in Germany). I used it to fix the fine adjustment potentiometer in old turntables.

Thanks for the suggestions all.
I’ll try starting from the terminal and see what it says.
I’m not 100% sold on hardware at this point, as it seemed to be working just fine in Serato, with the full range of volume control. I will check again when I have a chance. If it is giving me problems in Serato again I’ll try some fader lube or replacing the fader.

I am getting some debug info when I tested the controller, but nothing comes up for either volume controller, despite using them multiple times.

I did notice this when I first started:

Warning [Controller]: USB permissions problem (or device error.) Your account needs write access to USB HID controllers.

And to confirm, the volume fader is working error free in Serato Lite - volume range from 0% to 100% so I’m guessing this is a Mixxx issue.

I don’t know how 4-channel control is handled in Serato, but regarding the Mixxx issue I still suspect there’s dirt on the fader resistor and some values are missing.
To test that you can open the loaded script file in Pref > Controllers > Mixtrack… and disable softTakeover here https://github.com/mixxxdj/mixxx/blob/master/res/controllers/Numark-Mixtrack-3-scripts.js#L746

Maybe you don’t have permission to edit the file (depends on OS). In that case you need to copy the mapping files to %mixxx_user_dir/controllers/ (in the same folder as the log file https://github.com/mixxxdj/mixxx/wiki/Finding%20the%20mixxx.log%20file):
the base mapping (xml) is copied to that directory as soon as you change anything in the mapping in Mixxx (altering a description in the Mapping > Input tab should suffice). There you can also open the script file and copy it to the same directory.

I just noticed we already have an easier way to get to the folder with the user presets:
simply go to Pref > Controllers and click the “User Preset Folder” button

Just a quick update - this issue seems to be resolving itself. After not having touched the controller for nearly a week, I plugged it in last night and in Mixxx it travels nearly 100% and when it bottoms out it’s maybe about 10% volume.