The vital components will likely be located in a water-and-weather-resistant casing. Might have some sort of faraday cage over them as well, but an EMP is always worth a shot.
The idea, though, is to render the robot harmless while damaging it as little as possible. The most important thing is to figure out how to directly interface with the android's computer.
On another note, research should be done in a remote location, separate from your main headquarters, as the androids will undoubtedly be able to transmit location info to other bots. Actually, that's probably the first thing you should disable. Granted, anyone who's watched Terminator: Salvation knows that.