(Unsolved) Virus C MasterVolume knob issue

[stereotrope]

Hi,

I have a Virus C since two years now, latest OS up date...everything was working very well since yesterday...

I use the Virus in Multi Single Mode, controled by MIDI by a EMU XL7.

I m using Part 5, on Midi channel 5, audio out 1 R, and part 6, MIDI channel 6, audio out 2 R.

I dont understand how it is possible...but the Master Volume knob now doesn t affect the volume on part 6....there is no way to turn off the volume using the master volume control on part 6...but it is still working well for part 5...

I m stuck and don t find anything related to this issue in the user manual...if someone can help...

thanks