[NumBeast]

No, we even kept the same cables. Literally while the code was running we tried the sonar, and got valid distance values. Then while the RC was still running, we unplugged the sonar, and swapped it with one of the new ones. Immediately we got invalid distance data. It's not a problem with resetting or anything, because afterwards, while the RC was still running, we unplugged the new sonar, and plugged in the old one, and received valid position data. We followed the same procedure for all three of the new sonars. So we know for a fact it is a problem with the sonars.

If you recently purchased working sonars, it's probably a defect in ours. I'm a little unwilling to accept that too quickly though, because it's three sonars, not just one.