Jaguar Meltdown

[Peter H]

Our team (1606) had an interesting night tuesday when one of our jaguars released a plume of smoke while driving, all wiring was correct and the replacement jaguar is doing fine so we hope its just one that was faulty. upon further inspection after taking it apart it appears one of the power transistors had completly melted and began melting a second one and there were burn marks in the casing. has anyone else had this problem? pictures to follow...

[Urban Hawk]

here is a site for you to look at:http://tom-tech.com/first/wiki/image...ingStarted.pdf
there is a possibility the airway was blocked causing it to overheat.
also make sure you cap the PWM value using the calibration procedure listed in the document so it isn't at full.

[Peter H]

airway was completly clear and our team leader says the pwm wasnt a problem. heres what it looked like...





after this the fan was checked and was still working fine

[JBotAlan]

Just pointing out the obvious--traditionally, Victors have failed because teams have gotten metal shavings inside them; the team I was on as a student included. Are you absolutely mega-sure that this didn't happen? It is very easy to do, especially if the person with the drill doesn't fully realize the potential for disaster...

As for the team I'm with now, we haven't had the robot moving much at all, so we haven't put our Jags through their paces. If one of them self-destructs, I will definitely post back here.

You may wish to contact FIRST if you believe this failed under normal circumstances.

Jacob

[Urban Hawk]

the picture that you had on there is a victor.... not a jaguar. here is a document i found online that may help you:
http://www.robotmarketplace.com/V883UsersManual.pdf

p.s. that is a bad picture of it

[JBotAlan]

Originally Posted by Urban Hawk

the picture that you had on there is a victor.... not a jaguar. Im going off to find another document to help you... hold on

This is a Victor. What was posted definitely is not.

[Peter H]

Originally Posted by JBotAlan

Just pointing out the obvious--traditionally, Victors have failed because teams have gotten metal shavings inside them; the team I was on as a student included. Are you absolutely mega-sure that this didn't happen? It is very easy to do, especially if the person with the drill doesn't fully realize the potential for disaster...

As for the team I'm with now, we haven't had the robot moving much at all, so we haven't put our Jags through their paces. If one of them self-destructs, I will definitely post back here.

You may wish to contact FIRST if you believe this failed under normal circumstances.

Jacob

absolutley we always cover all electronics when we do anythiong and we didnt find any foreign material in it when we opened it

[kc2pix]

Same thing happened to us!
(sorry the picture is bad. the burnt one is on the left)

[JBotAlan]

There's now 3 separate incidents that I see where a Jag has blown; two on this thread and one here. I hope that this is the end of it, not the beginning.

Better contact FIRST. You could ask on the Q&A, or e-mail them (unless someone else has a better suggestion).

Meanwhile, it's probably best to go back to basics if you can--use Victor 884s. They've been proven. Too bad there's not more of them in the kit this year.

Jacob

[Urban Hawk]

i have the manuals for the speed controllers so here they are:

for jaguar:http://tom-tech.com/first/wiki/image...ingStarted.pdf
for victor 884:http://www.ifirobotics.com/docs/ifi-...nual-dec04.pdf

looking at them the most likely problem may have been wiring since that seems to be one of the best ways when it comes to wrecking a victor so id suggest looking at the wiring guidelines section for the victors since it does list at the end several things you shouldn't do. For jaguar there isn't much on the manual about faults however on the first page there are 3 warnings of things you shouldn't do.

[dbeck103]

Being one of the beta teams we had one do exactly what you had happen - it smoked the transistor - Since then we have had two other failures. Luminary Micro has been great about replacing them and trying to determine why they are failing. Ours both failed in drive mode. Please contact Luminary Micro for help if you have failures.

[Al Skierkiewicz]

This is the destruct problem with conductive debris. Remember that the full power supply is available on the FETs when the power is turned on. If a chip should contact the Source and Drain pins on one FET 12 volts will cause full current to flow limited only by the action of the breaker feeding the controlller.

[Racer26]

I am currently holding in my hands a Jaguar that smoked about 90 minutes ago, and looks inside very similar to the above pictures. Upon disassembly, no obvious metal debris is present. Email already sent to LM for RMA.

EDIT: upon closer inspection of the above pictures, this one also appears to have smoked the chip on the lower right edge of the ring of FETs.

[Dad1279]

Originally Posted by Al Skierkiewicz

This is the destruct problem with conductive debris. Remember that the full power supply is available on the FETs when the power is turned on. If a chip should contact the Source and Drain pins on one FET 12 volts will cause full current to flow limited only by the action of the breaker feeding the controlller.

I think there is more going on here. We have not smoked a victor in 6 years, always very careful. Today we mounted a Jaguar, never drilled near it, and it smoked after less than 5 minutes of operation. No way there was debris in it, unless it was left over from manufacturing.

I will contact Luminary Monday, and send it in.

[Al Skierkiewicz]

Dad,
It is common for debris to vaporize in this kind of failure. So it is next to impossible to determine whether there was something or not that a foreign body was the cause. Make sure to contact luminary and return it. They are doing forensics to determine failures at this point.