Roland System-1 adjust Fine Tune (Pitch) OSC1

[molesmile]

I can't figure out how to fine tune pitch of OSC1.
Is there a hidden key-set-function to change the pitch of the OSC1?
I want to set my synth in-tune with my other analog synths which would be very handy.
I read in the new v1.20 Operation Guide that the master tune 440hz +/- can only be changed when holding the SYSTEM-1 during power on the device but not in perfoming (live) mode.
Thanks for your help.