Yamaha RX-11 Mods
 
 
The Yamaha RX-11 is a typical 1980's drum machine with a few nice features such as individual outs and  an internal transformer. The sounds are the usual Yamaha fare, some extra snare and kick sounds to choose from. I had one of these years ago, that I did some permanent damage to while bending it. I've since gained quite  a lot of knowledge about the Yamaha  RX series drum machines. I purchased this one on E-Bay for $25 about two months ago, and in preparation for the BENT festival, where I will be performing and leading a workshop on bending drum machines, I decided to finish this one off. 

WARNING: Electricity can do serious damage and can kill you ! Attempt this at your own risk!!!
Inside the RX-11, you will see a circuit board for the top row of individual outputs. You will need to remove the back plastic cover, and the 10 metal clips holding the 1/4" jacks in place. After these are removed, this circuit board can be folded back to expose the primary IC chips for these modifications.
To find th pin numbers listed for each IC chip, begin counting on the lower left corner of the chip, from left to right, and then from right to left on the top row of pins. The IC chips of most importance to bending this machine are:

   1.] YM 2154 - the biggest chip in this picture, with small and large pins. All connections should be on the large pins. BE CAREFUL, as permanent damage can be done to your RX series drum machine with improper connections on this chip. For this chip, I will attach an Atari style joystick connector to the following pins:
pin 59 - will be connected to the ground of the Atari joystick.
pins 39,41,43, and 45 will be connected to the directions of the joystick. 
The "Fire" button will be connected to YM 2190 (1), pin  number 11.
You can also use a 5 way rotary switch in place of the joystick for these same effects.

   2.] YM 3010 - located directly to the right of the ym 2154. I used three SPST switches connected to pins:
switch 1. is connected to pins 3 and 6
switch 2 is connected to pins 16 and 22
switch 3 is connected to a red LED with the positive lead connected to pin 5, and the negative lead to pin 19.

3.] YM 2190 - there are 6 of these directly above the ym 2154 chip, all bends on these chips are the same, meaning that you can use any of these 6 chips with the same results. Duplicating any connection on more than one chip will not produce any extra efffects. Connecting pin 2 to pin 7 on any chip will provide you with a nice bleepy interpretation of your drumbeat.