just got my hands on a DD-14 here..
since i'm not the "Let's poke around and hope we won't kill it" kinda guy, here's some info that might be useful..
on the MOSEL chip (IC3, ROM) pins #1 and #32 (the one on the corner near the dot and the one straight across) are both connected to the +5V rail. best to stay away from those.
pins #16, #22 and #24 all connect to ground. they're ok to mess with, but they're basically the same.
wired it up, looking for a way ahead (patchbay? keyboard? dunno yet). might take a while.
so far, i did swap out the 12Mhz crystal (cr1) which is responsible for overall computing speed. i felt the original slowest tempo was still too fast, so i put in a 8Mhz crystal. 6Mhz works as well, but then you can see the display leds starting to flicker and the whole thing's response becomes too slow.
i will be replacing the 9.4Mhz (cr2) ASAP with the LTC1799 kit sold here, since it determines readout speed = pitch.
i doubled all the red wires coming from the pads to hook up to triggers, sequencer or whatever - if you hit them with a +5v spike, they trigger the pad sound. applying 5v for longer creates a retriggered drone. makes the marimba sound like an alarm clock
oh, and less volts = less volume. was driving the drone up and down in volume with a doepfer envelope generator.. promising results, since the volume can be CV controlled!
@ phantompowers: mind me asking how you hooked up that 40106? i found a way to flash an LED in time with the beat connected across some legs of IC8, but i like the direction you took it in..