Vintage Synth Repair

Hello,  I have a crumar orchestrator that is in tune with itself, but which cannot be tuned to other instruments.  While there is a pitch slider on the front, it cannot go flat enough to put it properly in tune with a standard tuning.

Could anyone please point me to the proper adjustment point inside the synth so that I can realign the center of the pitch slider such that it can make useful adjustments? I'm a bit new at this...

I have uploaded  a PDF of the schematic to the Files folder on this group page.

Thank you!  DT.