18v7 damage (repair question)

Hello, I’m working on a project using the 18v7 motor controllers and we’ve been having a problem with them breaking. I guess it’s because we’re using too much current, so we’re looking into upgrading to either the 18v15 or 24v12, but we’d really like to try to repair the damaged ones if possible, so I was hoping I could get some advice. I’ve uploaded a picture of the damaged parts and they just appear to be transistors; does anyone know (a) the exact model of these transistors and (b) if replacing them would repair the motor controller (they still connect fine, we can communicate over USB/Serial, they just won’t power the motors).

imageshack.us/photo/my-images/84 … maged.jpg/


Hello, magician13134.

I’m sorry you’re having trouble with the Simple Motor Controller 18v7.

The transistors indicated in your picture are part of the H-bridge that drives the motor. They are N-channel MOSFETs and the package is SOT-23. We don’t give away the model number, but when you’re looking for good replacements it might help you to know that the maximum continuous drain current of the part is about 6 A at room temperature and the maximum drain-source voltage is 30 V.

It’s hard to say if replacing the transistors will fix the controller because there might be other parts of the board that are damaged that we don’t know about. Each of the transistors is in parallel with another one, so if you can cleanly remove at most one transistor of each pair, the controller should still function (but with less current). I would remove all the broken transistors, and see if you can still drive a motor at all. If you can, it’s a good sign that adding the transistors back will fix the controller.