i found this today at a market for AU$3,so far the only bend i could find was pitch control. i added a 1k pot and a switch and it goes down almost 2 octaves i also added a 1/8 output.
has anyone had any experience with these. is there anything else or is that the limit of what is on offer?
personally i love this keyboard. i wish i could find another one. it's the perfect platform for a diy synth project. on its own it doesnt do much. i know you can add a key hold switch to it. this would hold whatever key you last pressed forever... not sure how i did that. i may have just added a switch to one of the keys and kept it in organ mode. actually i think what i did was just fully connected one of the keys to give the key hold effect on the organ mode, and then bypassed the piano envelope to produce the original organ sound. to bypass the piano envelope all you have to do is connect a wire to the ground and poke around the transistors until you get a square wave envelope sound like the organ voice rather than the crappy piano sound it would have made. wow, i cant believe i remember that after two years... ok, heres a demo. i know this looks different than your keyboard but it is exactly the same on the inside.
demo (http://www.youtube.com/watch?v=UFeeh7ANf-Q#normal)
yeah it is quite funny. i only added a pot to control the pitch and a line out. but when i plug in a cable, and press the piano button it has the infinite keypress.