Am still new to the 168RC, but monitoring from the dat I'm
recording to, the master fader does not raise or lower the
signal, while the individual channel faders do.  BUT when I
monitor from the 168RC's headphone jack, the master fader does
raise or lower the signal in tandem with the channel faders.

I've turned on and off every possible switch, bus, grouping,
and read the manual thoroughly.  All it says in troubleshooting
is I need to "hook" the fader (master fader doesn't have a "Sel"
to hook with) or check the midi setup.  I've turned off all midi.

Baffled, totally.