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Unread 30-03-2010, 11:59
Oblarg Oblarg is offline
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AKA: Eli Barnett
FRC #0449 (The Blair Robot Project)
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Join Date: Mar 2009
Rookie Year: 2008
Location: Philadelphia, PA
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Digital sidecar PWM controller failure

Recently, we built a practice robot to get in some more driver practice and test additional mechanisms before our next regional. The robot was working fine, until suddenly the Jaguars started reporting that they were receiving no signals. After a few hours of troubleshooting, we had no ideas as to what could be wrong, except that the relay lights were on but looked as if they were receiving half power.

A day or so later, we procured a second DSC, and wired it. The robot worked fine for about 5 minutes, but then the jags reported again that they were receiving no signal. The relay lights also started lighting up as if they had half power. We took the cover off of both of the DSCs and found that the C6 capacitor had been knocked off of both, but we found later that this is a known issue that should not result in DSC failure. We also noticed that the PWM controllers on both smelled very burned. We've checked every PWM cable for resistance, and all are correctly isolated. None of the power wires on the digital inputs are connected. None of the servo jumpers are in.

Does anyone know what could have caused this, or what steps we could take to avoid it in the future? Were are heading to North Carolina with our only remaining DSC, and would like to avoid killing it.
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Member, FRC Team 449: 2007-2010
Drive Mechanics Lead, FRC Team 449: 2009-2010
Alumnus/Technical Mentor, FRC Team 449: 2010-Present
Lead Technical Mentor, FRC Team 4464: 2012-2015
Technical Mentor, FRC Team 5830: 2015-2016