Grey Jaguar No Power Out

[ajlapp]

We have a Grey jaguar that appears to be in normal working order except it has no power coming through the output...

The device is wired properly. The device's indicator is responding appropriately to commands...we are getting full red and full green led feedback.

We just don't get any juice to the output. Is this as simple as "the jaguar is broken?"

Thanks for any insight.

[ATannahill]

I'm guessing you mean your motor doesn't move. I am also assuming you are using a DC 12 volt motor. If I am wrong tell me.

First thing to do is check the output with a voltmeter and see if you get any power through.

If that comes up flat I would check if the code thinks that out put is a victor. That has caused weird results for us.

[Mark McLeod]

If the limit switch jumpers were missing, then you'd also get those symptoms - red/green LED but no power out.

[ajlapp]

First thing to do is check the output with a voltmeter

I checked that first. Also, this isn't an FRC application.....so there should be no mystery code issues.

If the limit switch jumpers were missing,

The limit switch jumpers are in place.

[Radical Pi]

Originally Posted by ajlapp

The limit switch jumpers are in place.

Are they in the right direction (vertical)? I remember someone on our team once flipped them horizontally and it did something like that

[dyanoshak]

Originally Posted by Mark McLeod

If the limit switch jumpers were missing, then you'd also get those symptoms - red/green LED but no power out.

That isn't entirely accurate. When the limit switch input is open (no jumper), you will get a slow blink red indication on the LED if you try and drive the Jaguar in the direction with the open limit switch.

Are you using PWM or CAN to communicate with the Jaguar?
Is this a brand new, out of the box Jaguar?
Have you noticed any ESD (Electro Static Discharge) events?
Have you unscrewed the screw terminals completely (aka using ring terminals)?
Metal shavings in the case?

-David

[ajlapp]

Are you using PWM or CAN to communicate with the Jaguar?
Is this a brand new, out of the box Jaguar?
Have you noticed any ESD (Electro Static Discharge) events?
Have you unscrewed the screw terminals completely (aka using ring terminals)?
Metal shavings in the case?

We are using PWM.

Not new.

No ESD.

We are however using ring terminals....I did notice in the manual that it says these shouldn't be removed completely. It is possible that there are metal shavings in the device.

[Al Skierkiewicz]

Tony,
There is a possibility that there is shavings in the device. However, if it is an older jag, it might have succumbed to the dreaded FET driver failure. It is also possible that the current sense resistor has unsoldered itself. This leaves the low side of the output stages open. I do not know if the firmware checks for that condition but I have opened a few Jags where this has occurred. As others have hinted, be sure that the terminals have been correctly crimped by checking the output of the Jag with a voltmeter. The resistor lives near the negative input terminal (upper left when viewed from above with the jumpers toward you) and is the largest surface mount resistor in that area.

[ajlapp]

I left this unresolved for now......I grabbed another Jaguar in the meantime.

I suspect that I will find shavings inside at some point.

Thanks for the help. I was able to get the machine up and running with no problems.

[Tom Line]

Originally Posted by ajlapp

I left this unresolved for now......I grabbed another Jaguar in the meantime.

I suspect that I will find shavings inside at some point.

Thanks for the help. I was able to get the machine up and running with no problems.

Anthony, once upon a time the folks who make the Jaguars were excepting returns for troubleshooting. You may want to contact them (you can find them in a more than a couple threads) and see if they're still taking return / swaps. You might get lucky and get it replaced for free.

[Ether]

Originally Posted by Tom Line

You may want to contact them ... and see if they're still taking return / swaps. You might get lucky and get it replaced for free.

As the old saying goes: "If you don't ask the question, the answer is NO"

[ajlapp]

Good thinking....I'll ask.

Though I read in the manual explicit instructions not to completely remove the terminal screws.

I see they changed that with the Black Jaguars.

[dbeckwith]

My team was having this exact same problem, thanks for all the possible problems to try. We ended up getting another Jag anyway, but if we can fix our broken one then at least we have a backup.
I know we've unscrewed the terminal screws several times, so we could have shavings. I don't think it's the program or jumpers, I've checked those, and I think I would have noticed if the current sense circuit was unsoldered when we opened the Jag. I saw something in the Jag manual about calibrating the PWM signal, so I might try that. It could also be one of the MOSFETs. Anyone know a way of testing if any are blown and/or how to replace a broken one?

[Al Skierkiewicz]

Daniel,
The current sense resistor might not grab your attention if is missing. This was the case in some of the devices I inspected. Generally, when a FET goes bad, it leaves a burned area around it. The plastic FET retainer/insulator will be melted and there will be black marks on the board as well as burned circuit board traces. If the FET is open, you can measure with a VOM. Use the diode test position on your meter if it has one. In general with a failed FET gate driver, there is no visual damage. However, on several I have examined, the FEET driver chip had blown apart one corner and left a crated on the board.

[dbeckwith]

I can't see that any of these problems are what's wrong with our Jag. The only visible thing I see that's different with the diagram in the manual is an extra resistor connecting R25 and R24, right under the current sense resistor. All our Jags seems to have it. The color bands go gold, yellow, purple, yellow. I realized also that the one we have that isn't working is one of the four we got in the rookie kit last year but have never used until now, so it's actually never worked, but all the others have. Is that resistor supposed to be there?