Vintage Synth Repair

To All,

I have the subject keyboard and I am trying to permanently turn-off the
split keyboard function on some of my presets. I tried it as the book says,
go into preset with split, edit, select split/drawboard (#6) twice, move
cusor to off, hit save and get out of preset. Once I get out of preset in
question and come back to same preset split is still on. It is driving me
nuts and want to get problem solved. Would appreciate any help you can
provide. 

I know its something stupid, but I am out of patience and need some help. 

Also looking for a schematic for the keyboard. 

Please advise when you can. 

Chuck 

PS I have version 2.0 of the software.