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jgraber

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Reply with quote  #1 
I saw a new (to me) failure mode for Cortex at Dallas BEST Game day.
Symptoms:
- "Robot drives funny" since one wheel is under powered
- Robot on jackstand so wheels can spin, drive forward, and hold wheel back by hand
** wheel on port 2 stalls and shakes;  Other wheel on port 9 is pulls harder until it stalls. 

Diagnosys:
- Changing motors didn't change behavior, so its not the motor
- Same behavior both forward and backward wheel rotation, so it isn't just half-bad Hbridge.
- Changing MC29 controllers didn't change behavior, so its not the Hbridge at all
- Swapping wheel motor ports from 2 to 9 moves problem to other wheel,
* Problem is on port 2;   

Hypothesis: port 1-5 thermal fuse is tripping too quickly.
- Additional tests not yet performed: try other ports on that fuse, ports 1,3,4,5

Workaround:  swap out cortex for a different one,

Lesson Learned: always have your programming computer ready to program a spare cortex, since a spare cortex without your program is nearly useless.
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