Casio SA-2: ALL features of SA-1 with ONE switch

[Nixot]

Hello everyone,

I've been poking around my SA-2 with the help of the knowledge found in this forum and a little of my own reasoning to discover a couple of bend points that will give you every feature of the Casio SA-1 using only one DPST switch (or two ordinary switches). The way it works is by mapping the hidden functions to the keyboard keys. I discovered this when I noticed that the hidden sound select switch mod also controls other things, and in fact the first eight keys all did something different, e.g. pressing Bb increases the tempo. There was a matrix of what happens if you connect one pin to another somewhere on this forum, and I discovered that it was redirecting all the signals from one pin to another. So, I altered the position of one wire to get to push buttons 6, 7, 8, 9 and 10. With it, I also got loads more features, which led me to think - if I connect both pins to different groups of notes on the keyboard, I'll get both sets of features. It worked! Yay! So, I believed that the community should hear of this discovery. So here it is:

Step 1: Solder a wire to pin 30 (all these pins are on the OKI chip). Solder another wire to pin 26.
Step 2: Solder these wires to the first set of pins on the DPST switch (or one switch).
Step 3: Solder a third wire to pin 29. Solder a fourth wire to pin 25.
Step 4: Solder these wires to the second set of pins on the DPST switch (or another switch).
Step 5: Turn on the switch (or both switches) and press the buttons according to the diagram below:

F: Button 1 (0 on SA-1)
F#: Button 2
G: Button 3
G#: Button 4
A: Button 5
A#: Tempo Up
B: Volume Up
C: Select Rhythm (a bit useless since it will automatically select Disco 1)
C#: Button 6
D: Button 7
D#: Button 8
E: Button 9
F: Button 10
F#: Stop Rhythm (good for dramatic contrast as it will play a note)
G: Tempo Down
G#: Volume Down

So, using the chart above, you can write them on the keyboard keys and have every function available to you, without loads of complex wiring and buttons clogging up case real estate best used for the wacky effects you can make with it.

Hope I was of use!

[Circuitbenders]

somebody give that man some karma 

[druzz]

thanks for sharing .  i have a sa-2 and a sa-20 to bend in the near future .

i dont get what are the buttons 1-10 though . are they the tone buttons used to get the missing tones ??

[Nixot]

Yes, on the SA-2 there are buttons 1 to 4 which correspons to buttons 0 to 3 on the SA-1. There are six addable buttons which correspond to buttons 4 to 9 on the SA-1.

[jamiewoody]

has anyone hooked up a 555 lfo to this? i hooked up an apc circuit as a filter. it sounds very synthlike! ;-)

[Nixot]

i hooked up an apc circuit as a filter. it sounds very synthlike! ;-)

Sound demos please.

[jamiewoody]

actually, i'm uploading a vid to ytube as we speak! ;-)

[Nixot]

actually, i'm uploading a vid to ytube as we speak! ;-)

Cool, can I have a link?

[jamiewoody]

it's up...look for sa(pocolypse)2 on the "synths" forum

[argossummergiftguide]

Hey guy, I've been bending my Casio SA-2 and getting to grips with a few of the bends on here, added the volume, drum pads out, I added a power crash out. Since then, something has happened, my keyboard only plays at a really low volume through the speaker and aux out even when i disconnected the power crash mod and made sure nothing is short circuiting... reckon I've blown the op amp, it is possible that I hooked it up to 9v adapter by accident (even worse, I may have even reversed the polarity)? how would i find out if I've blown it? any suggestions, could I have blown something simple to replace?

[iwillbeacircuitbender]

I believe if you look on Chinese part suppiler sites, you should find the amplifier chip for your SA