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Originally Posted by Al Skierkiewicz
Is there a possibility that your controllers were mishandled before install? i.e. students walking across carpets and picking up the controllers. Were they ever used in another application, testing or demo? Ever installed near bare metal or wire? Ever connected directly to a battery and motor outside of a robot without circuit breaker protection? ...
Have you disabled the dead zone in software? Is there a possibility that the controllers were always "on" just a little? Do you calibrate the controllers? Can you show a picture of how they are mounted in your robot?
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There's no sure way of always knowing how students handled the controller's while the engineers weren't in the lab. While I was there they were being careful, but there were a lot of new students this year. The lab has no carpet, but clothing could still generate static. As a related measure we didn't have trouble with the IR sensors being blown by static electricity as some of the other teams I was helping did, but that was a different sub-group with a much more limited number of students.
The electrical layouts were reworked many times as mechanical designs changed, so there was a lot of controller handling (but no powering up).
Some of the controllers were taken off last year's robot when we started to run shy, so those were reused.
They were never used or installed without circuit breaker protection, or near bare wires.
We've never blown victors before, so initially we thought it was foreign object debris, but your description of the damage caused to the Victor case and the lack of other evidence seems to reduce the probability of that as a cause.
The dead zone is restricted by software with a smooth increase in power outside the dead zone compatable with the measured Victor deadzone. We verified via the dashboard the PWM output as neutral when it should be. The new joysticks didn't usually center properly (weak springs). The blown Victors were a mix of factory calibrated and team calibrated. We did calibrate all later ones, because we weren't measuring full power out of the Victors in bench tests with the factory calibration.
We had an issue early on with the drill/CIM victors receiving 127 according to the dashboard, but sometimes passing low power through to the motors anyway. That could be a related symptom. That problem also seemed to be gone by Nationals.
The wiring photos I have don't show the Victor mounts clearly. I'll have to wait for the robot's return from Nationals.
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Originally Posted by Matt Reiland
Which FET's did you use to refurbish your Victors, seems the guys repairing them on the Battlebots forums are finding the matching replacements costing MUCH more than .90 ea??
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I'll check on the actual FET price and source (retail or wholesale) and get back to you.