MC6 Freezes with Exp Pedal

Hi, I have an odd issue that when I have a Boss FS-7 expression pedal plugged in, I can consistently recreate a full freezing event. Ive tried a number of steps outlined below.

  • Confirmed both MC6 Exp 1 & 2 were set to Aux Switch, issue can be recreated on both ports.
  • Device sending Expression = Boss FS-7 - Tried both A and B ports, both fully freeze MC6
  • Same TRS cable plugged into simple 2 switch aux pedal works fine no issues.
  • With FS-7 on Momentary, no power, Polarity I - MC6 completely freezes still, no button usage on MC6 registers. MC6 connected to USB sends no midi through a Midi Monitor until FS-7 is unplugged. Same issue with Phase I or II, Momentary or Latch on unpowered FS-7
  • When FS-7 is powered up, MC6 will unfreeze when FS-7 switch is engaged and refreeze once FS-7 is disengaged on Polarity I. Reverse experience on Polarity II, MC6 operates until FS-7 is engaged which freezes MC6
  • If I cause MC6 to display brief message such as Bank switch, then plug in FS-7, MC6 will stay at the message screen and never revert back. The only display that responds is “In Edit Mode” and “Existing Edit Mode” if I enter/exit editor on Mac.

Google Drive - Controller Settings JSON file

Edit: I found the FS7 Knowledge Article, perhaps this is expected functionality. I’ll use powered and Polarity II

Yes, the FS7 needs to be powered in order for it to work as a momentary Normally Open switch.

When the MC6 “freezes”, it is because it is reading the aux switch as being pressed down.