Arduino Duemilanove with Adafruit motor shield causes piggybacked motor drivers to overheat- even with no load. Ideas?
I have an Arduino Duemilanove and an Adafruit motorshield. Both work fine, but the motors I want to run require more current than the available 0.6 amps. I tried piggybacking two more drivers on top of the existing ones, but now when I turn it on one set of chips overheats immediately. It's not a soldering error, because I've tried it with many different chip configurations and the same problem occurs. The only thing I've noticed is that the new drivers I purchased have slightly different numbers under the customary L293D- but isn't that just when and where it was made? Any ideas?