Brick behaving improperly

[rhsteach]

I am working with several robots. A simple program, which works on one robot, does not work properly on another. I have tried re-flashing the brick without any change in behavior. A command such as Motor.C.rotate(20) will cause the motor to turn for numerous rotations rather than 30 degrees. A command to the pilot to travel(80) starts the motors turning indefinitely. I'm wondering if some memory is not clearing. I reloaded the Mindstorms software, then flashed the brick again, but with the same results. Any suggestions to correct this?

[gloomyandy]

Is this just the one NXT? Have you tried swapping motors and cables with an NXT that works? What happens if you write the same sort of program using the Lego software?

[skoehler]

It might also be the cable - or a particular motor port. So make sure to also try another cable and another motor port.

[rhsteach]

After more experimentation, I believe the problem is the brick itself. I found out how to do a hard reset of the brick, which I did. I reloaded Mindstorms and discovered it has the same issues: a command to the motors to turn by degrees or rotations results in the motors turning continuously - similar to what was happening in Lejos. This happens with all 3 motor ports. Curiously, the command to turn for a period of time works properly in Mindstorms - haven't tried that in Lejos.

Another new thing I noted is that the brick seems rather hot.

Bottom line: I suspect I have hardware failure. However, I would be delighted to be wrong if someone has a way to rescue me.

[skoehler]

After more experimentation, I believe the problem is the brick itself. I found out how to do a hard reset of the brick, which I did. I reloaded Mindstorms and discovered it has the same issues: a command to the motors to turn by degrees or rotations results in the motors turning continuously - similar to what was happening in Lejos. This happens with all 3 motor ports. Curiously, the command to turn for a period of time works properly in Mindstorms - haven't tried that in Lejos.

That's no surprise as the mechanism for measuring time and the one for counting the number of degrees the motor has rotated are not related at all.
Or in other words: counting the encoder ticks returned by the motors seems to be broken. That does however not impact rotating a motor for a certain amount of time.

Bottom line: I suspect I have hardware failure.

I think that too. You might want to phone Lego and ask them whether they replace the broken NXT. They are usually quite polite.