[sdiy] Kurzweil PC-2 ribbon controller

[David Brown]

I got my PC-2 ribbon today from Sweetwater's.  I was close on the pin 
out information.  I located a drawing for a RJ-11 connector and 
labeled the pins on it.  I put it on my website at the bottom of this page:
http://modularsynthesis.com/modules/DJB-011/djb011.htm

I had the + and - connections to the ribbon backwards (although it 
depends on the orientation of the ribbon.  I have the ribbon with the 
cable exiting to the left.  In this orientation, the left and right 
ribbon sections increase in voltage to the right (when wired as 
dividers).  However, the middle ribbon section is reversed going from 
high to low voltage.  Wonder why?

Now to write a PSIM program for a single or triple ribbon 
controller.  I think I will wire 100K resistors from the 'wipers' to 
a voltage higher than across the resistors.  That way I can tell 
whether the ribbon is in contact (output voltage between the resistor 
voltage) or not in contact (output voltage higher than the resistor 
voltage).  I'm thinking that just a diode drop would do.  I can run 
the ribbon off of +5.7 volts with each section at +5 volts.  That way 
I can do a return to center and know when to output a gate.

Comments or suggestions?

Dave


At 11:58 PM 3/30/2006, David Brown wrote:
>Found it.
>
>Here's what I wrote down from measuring my Expressionmate ribbon.
>
>I measured resistance from 30 ohms to 4K (guess they weren't 20K)
>
>Pin 1 common- (low end of the 'potentiometers')
>Pin 2 common+ (high end of the 'potentiometers')
>Pin 3 mid ribbon 'wiper'
>Pin 4 left ribbon 'wiper'
>Pin 5 right ribbon 'wiper'
>Pin 6 n/c
>
>Pins are numbered from right to left with the tab on top.
>
>Dave