Just went through your original thread about this.
Assuming nothing has changed with Logic 8 + dual core this is most likely hardware failure due to 10 years of use. This can be fixed by replacing the offending knobs/faders/switches or better still replacing all of them if you really love the unit.
try cleaning the pots and faders with some switch cleaner then re-lubing but tbh 10 years is natural hardware failure imo.
I'm not a logic user but the generic answer to your question applies...
When this shit starts happening with any midi controller (if you can) try the unit on one or more computers. If it happens elsewhere it's probably hardware related.
If you can't do that then start by checking the midi data in your daw's automation lanes to see which controllers are sending the random data. Once you know this you can try a bunch of things.
- Try manually assigning the problem control to something else and see if it still happens.
- If using a template in logic double check the assignments there.
- Double check the logic preset on the mpd itself you might need to reload that or change it.
- Try the "Kill Midi" function on the mpd which resets all parameters back to 0.
- Consider resetting the mpd back to factory default then re-loading templates or re-mapping custom shit.
- Check the firmware version on the mpd.
- Check your power supply and/or try a different usb cable.
- Yes you can filter cc messages by setting a threshold min/max but I have no idea how that's done in L8.
I could go on. Hit up the manual and try some of that shit for now.
Edit: I moved this back to the producers section.