Cheap Mods
Junior 106 Octave Switch Circuit













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This is just a page to hold the schematic for my Junior 106 Octave Switching circuit (sorry for the cruddy scan, but it is readable...).
 
When you make a Junior out of a Juno, you chop out a significant chunk of the keyboard; sadly it's the lower register which means you lose that wonderful 1 DCO Juno bass sound, unless you use this circuit.
 
This circuit allows you to "fool" the keyboard matrix scanning circuit into thinking that you're now playing the lower registers of the keyboard.  Basically, a single physical SPDT switch drives several SPDT analog switches (CD4053), which switch the 5 matrix lines coming from the keyboard to different sets of the 8 matrix lines coming from the microprocessor.
 
Once again, credit to Henrik Nydell for inspiring me and showing how the Junior-106 could come to be!

junior106_octaveswitchcircuit.jpg