Quote:
Originally Posted by Al Skierkiewicz
Chris,
If these are very old PDs then there was an issue that a capacitor was too close to the edge of the board. It sometimes would get knocked off and find it's way into another area of the board. These devices are very easy to open up and inspect. Look for missing parts or smoke damage on the board. Also look for evidence of burned circuit traces.
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Al,
We did open them both to see if there were any obvious problems. No smoke damage and the conformal coating was intact. That's when one of the electrical mentors asked for the schematics to look at, and the question was posted. Thanks to 3992 for the datasheets and schematics. I've printed them and will give them to the electrical mentor for use in debugging the problems.
As for why they stopped working.... that seems to be the question of the day. PD board 1 was working last week, we were using it to test the new talon motor controller. The setup was taken apart and transported to Kettering University on 1/6/13 for the Strategy Dictates Design workshop put on by the EngiNERDS 2337 and returned to our shop. It may have been dropped/jostled/mishandled at some point during this time. We may never know. I will let the mentor know that a component near the edge of the board is sometimes the culprit for a PD to go non-functional.