Possible bad Jaguar.... Thoughts?

[Ken Streeter]

Originally Posted by PhilBot

Hi

I suspect I have a bad Jaguar, but thought I'd post here just in case.

...

Tonight I'll probaly have the elec. student swap out the Jag, but is there anything else I can try to fix this?

Phil,

My first thought would be rather than just "swap out" the Jaguar with one off of the shelf, I would be inclined to physically remove the suspect Jaguar from the robot (disconnecting all of the wiring first) and then move the suspect Jaguar to the position of the other swerve Jaguar that is working correctly, swapping the "good side Jaguar" with the "bad side Jaguar." When doing this, the idea is that all of the cabling (power input, motor outputs, CAN/PWM, and encoder/limit switches, if relevant) do NOT move with the Jaguar. You want to move the "suspect Jaguar" to the position of the "good Jaguar" and use all of the cabling for the "good Jaguar." Similarly, put the "good Jaguar" into the position previously held by the "suspect Jaguar" using all of the cabling from the "suspect Jaguar." You can then retest the robot with the "suspect Jaguar" and the "good Jaguar" swapped.

I see four possible outcomes from this, each of which would tell you something about what is wrong:

A - the problem moves to the other side of the robot: this is almost surely a bad Jaguar. Contact TI to RMA the Jaguar (assuming it is a black Jaguar).

B - the problem stays on the same side of the robot: the problem isn't with the Jaguar at all, but is being induced by mechanical or cabling issues

C - the problem goes away completely and both Jaguars work fine in their new positions: there was likely a mechanical or electrical cabling issue (loose connection) that was fixed by the act of unconnecting and reconnecting everything

D - neither Jaguar works: either the disconnect / reconnect was done sloppily and there is now a loose wire/cable on both sides, or there was some sort of mechanical/electrical issue on the "bad side" which had induced a fault in the suspect Jaguar and has now induced a fault in the previously good Jaguar, too.

In any case, I'm curious to hear the results of your troubleshooting, whether or not you end up trying the swap I describe

Best Regards,
--ken