U2D2 board overheating

We had a U2D2 catch fire, and the replacement is getting very hot.

We are using a U2D2 and U2D2 power board to run six XM430-350 motors as part of a robot. The motors are connected in two strings of three to the power board, and each string has a total length of ~18in.

The power board is provided 12v power from an AC-DC power supply through the molex connector. The SBC is provided 5v power from another AC-DC power supply, they are both connected to earth-ground, but to not share a common DC ground except through the U2D2 / USB connection.

During operation, controlling the motors at 50hz, the U2D2 TTL driver chip gets very hot. After shutting down our control script we had one U2D2 overheat at catch fire. We have not seen that behavior repeat and it may be separate, but even during normal operation the U2D2 gets very hot while in use.

Any ideas? Thoughts? Clarifying questions?


XM430-W350 (x6)

DYNAMIXEL Controller:


Software Interface:

Python SDK, protocol 2, over USB with a baud rate of 1M and 1ms of usb latency. We are sending individual read/write commands to each of the dynamixels and not using the batch variants at this time with the exception of our e-stop’s torque on/off commands.