MIDIfication Korg C-26 Electric Piano

[ilmenator]

Hi,

 

I have an old Korg C-26 electric piano that has broken down, so I'd like to give it a second life with MIDIbox KB. The keyboard scanning schematics look very much like Type #2 Keyboard EXCEPT that it has common cathode instead of common anode diodes configuration. In other words, the diodes are inversed.

 

Now, I could remove all diodes and solder them in the opposite way, but I'd rather have this solved in software if possible. How?

 

Thanks, ilmenator

[TK.]

Easy :smile:

 

set kb <1|2> din_inverted <on|off>

This option should be enabled if diodes are used with the opposite polarity, and pull-downs are connected to DINs.
Examples:
set kb 1 din_inverted off: diodes with "normal" direction and pull-up resistors at 74HC165
set kb 1 din_inverted on: diodes with opposite direction and pull-down resistors at 74HC165

 

If you are using the MBHP_DIO_MATRIX module, the pull-ups can be turned into pull-downs by switching the J6 jumper.

 

Best Regards, Thorsten.

[ilmenator]

Thanks TK,

 

I could finally get my hands on the schematics of the keyboard, and it all makes sense - but, the sad part is that this keyboard seems to be organized slightly differently than the Fatar ones, see below. I am sure this can be accommodated for in software!? It looks as if the keyboard was not split into separate halves, so we have 2 different matrices (one for the "early contact", one for the "late contact"), each of which is in a 6x15 configuration.

 

Best, ilmenator

 

Edit: I had it wrong again, this is now hopefully how the keyboard is organized...

Edited November 1, 2013 by ilmenator