Joe,
If a Jag was opened and metallic dust found inside, I think a vacuum is more appropriate. Compressed air will force some of the dust between or under the pins of surface mount components and under the shroud that surrounds the FETs. Many teams do not realize how much metallic dust is actually generated right on their robot. Open gears and sprocket/chain interfaces for instance throw a lot of fine metal dust while they wear. The big offenders are rotating or moving parts that rub against robot frames. i.e. arm attachments, shafts with no bearings, etc.
Thanks Joe! Unfotunately I’m working afternoons and midnights right now. Getting home at 4am is killin’ me, and putting a crimp on responding to chief delphi questions in a quick manner is a bit tough.
It has started again. We have already toasted two Jags from last year. We purchased a number for last year’s bot and removed them all from the robot after toasting 4. We just built a prototype drive base and in two days have smoked 2 of the “replacements” we got last year. Same symptom, it only loses one direction after issuing the magic smoke. I really wanted to move to CAN, but I CAN’T if I CAN’T rely on the Jags. Has anyone smoked a Black Jag yet???
PGR
Peter, are you covering the open connectors on the jags with tape, a plastic jumper, or something else? It’s been shown that direct static to the open jag connectors can cause issues.
Have you tested your frame to see if you’re running electricity through it?
Are you mounting your electronics on a conductive or a non-conductive surface?
Tom,
The direction failures are attributable to one of the power FET gate drivers shorting. I don’t remember if the cause of the failures was ever found or reported.
We smoked our first Jag today. I was a bit surprise how it decided to go up in smoke.
We did not have any failures last year. This was a brand new one just out of the box. It was not under any stress, and decided to smoke. It’s less than two days old. That’s too bad because I am sure Luminary probably doesn’t replace them because they assume you abused them. I hope we don’t have any more that die like this one. It was almost in “coast mode” and poof…
That seems like quite an unfortunate assumption to make considering that Luminary Micro’s Failure Analysis Report states that Luminary Micro promptly replaced every failed Jaguar last year.
Team 1279 worked on the Black Jag Beta program and we did manage to blow up two with static discharge, one by accident, and one on purpose (under TIs direction). Last years robots were very static prone, and the encoder and potentiometer inputs are fairly exposed. I would recommend covering the inputs with empty connectors when not using them to prevent that type of failure.
I would note that we also blew up our Kwik Byte driver station’s ethernet connectors when running tethered at a fundraiser, so the Jaguars are not the only static sensitive devices. Use due care with all your sensors, etc…
TI was very good to work with about the failures, and they seem committed to improving their product. I would say that any team who has a failure should contact TI, document the conditions, and return the blown part. The Jags have many cool features and I would very much like to see them become a reliable component.
Al,
I stated that because there was some discussion previously regarding the static. I wasn’t sure if it had been on the beta test boards or not, but the summarization was that static charge directly applied to the exposed terminals could create issues in the jags. I couldn’t remember who said it (fortunately someone spoke up here).
We’ll be using Jag’s again this year on our practice robot. I’m interested in seeing how they behave. We used them last year on our sparring-partner in the drive train and never experienced any issues with, though I know that anecdotal evidence is really of no help in determining their reliability.
Tom
Oh you silly Northerners! There is a simple fix to your whole static discharge problem…MOVE TO FLORIDA!
Sure, the education system isn’t as good and there’s a constant threat of hurricanes, but it’s not very often my car shocks me!
We didn’t send our failed and now failing Jags back to TI because we couldn’t determine if they were user error or production error. For instance, we have one which has been slowly failing for about 6 months. Was it from being outside at outreach events? Humidity? I don’t know. I think our original failed Jag was probably due to user error and I did talk with the TI rep at GSR. So there was some feedback.
Trying to Help