I bought a Boss DR-550 drum machine off of craigslist - how the heck do you accurately program a drum rhythm in this thing?

haha, it's got a bunch of numbers on a number pad (1-9 or something) and each one has a drum sound attached to it.

I've listened to the pre-programmed (or at least a few) beats.

Where does one start with such a convoluted machine??

look it up online, usually you can find a manual somewhere

www.bossus.com and look on support tab, sign up and you may be able to get it.

I tried to program our drum machine, and all he did was yell for more mountain dew...