[billbo911]

Originally Posted by Crazyboy

Hello!
I've been testing chassis with CIMs and Jaguar motor conterollers for the past few weeks now, and I've encountered a problem with a Jaguar.

It's always on.

To elaborate:
When testing the robot, they apparently had one motor go forwards immediately, without warning, the second the robot was turned on, it apparently started going. I've brought it back to my area and started testing on a simple electrical board we have set up. With or without a PWM wire connected to it, the Jaguar provides the same amount volts that the battery the system connects to provides. Additionally, I'm always getting connectivity across the V+ and M+ terminals.

I'd like to be able to fix this if I can, and I'm wondering if there IS a way to fix it so that it returns to it's previous functionality.


Thanks!

Originally Posted by Kevin Sevcik

It sounds like one or more of the FETs in the Jaguar's H-Bridge have shorted. There's nothing you can do yourself to make that Jaguar FRC legal again, as the rules prohibit modifying speed controllers. If it's a 2012 Jag, then you could RMA it. If you wanted to repair it for testing purposes, you'd need to crack it open and identify which FETs are shorted and replace them.

If you don't know what FETs are, how to identify shorted ones, and how to replace a surface-mount part, then I'd advise you to cut your losses and give it up for dead.

We have a Jag in our shop that is "always on". I opened it and it is obvious which FET is cooked. The plastic housing around the base of it is a melted pile.

I didn't notice which FETs are being used and don't have access to it right now. Does anyone know what replacement part could be used? Yes, it will not be legal for FIRST use, but it might still be recoverable for testing and learning.