Digital Sidecar Ports are dropping out.

[Mark Pendergast]

Team 1760 has had this problem as well.
I don't recall the exact details.
(We were in a hurry at the time and chose resolution over analysis.)

We lost one on the low end (1 or 2) during a practice run before we shipped.
We also lost another one (6 or 7?) when we were testing SW in our shop before we shipped.

Fortunately no problems at the regional.

[EricVanWyk]

Originally Posted by Mark Pendergast

Team 1760 has had this problem as well.
I don't recall the exact details.
(We were in a hurry at the time and chose resolution over analysis.)

We lost one on the low end (1 or 2) during a practice run before we shipped.
We also lost another one (6 or 7?) when we were testing SW in our shop before we shipped.

Fortunately no problems at the regional.

In the future, please choose resolution AND analysis. We can't improve without data.

[cabbagekid2]

Team 368 sort of had this problem also. Sort of beacuse the PWM still works...it just only works in driving the motor in one direction. One of our PWMs (I believe 8 or 10) only allows the motor to spin in one direction. We swapped PWM cables and it still didn't work. We know it's not programming since it worked fine for most of the Hawaii regional.

Since we were using all 10 PWMs on the digital side car, we ended up swapping the half broken PWM output with our shooter flywheel (since the flywheel only spins in one direction anyway).

[Tom Line]

CabbageKid2,

That sounds very much like one of the standard Jaguar Failure modes. Are you running a Jaguar on that PWM, and have you tried replacing it as part of the troubleshoooting?

Eric, I'll PM you my info.

[rspurlin]

I don't remember any problems with PWM signals, but we did lose the GPIO on one of our sidecars. We only needed one sidecar so we were OK for our regional. I'd still like to know what happened.

[cabbagekid2]

Originally Posted by Tom Line

CabbageKid2,

That sounds very much like one of the standard Jaguar Failure modes. Are you running a Jaguar on that PWM, and have you tried replacing it as part of the troubleshoooting?

Hi Tom,

We don't believe it's the speed controller because once we changed the PWM port that it's plugged into it worked fine again. So once it worked, there was no need to change the speed controller.

But anything that was plugged into the bad PWM output only worked in one direction.

[Mr. Lim]

We too had a DSC lose PWM signal on outputs 9 and 10, and the remaining PWMs continued to function fine. We noticed that the separate small buffer chip that drives PWM outputs 9 and 10 become EXTREMELY hot during operation.

We suspect that the failure may have been caused by an ESD event when disconnecting a PWM connector from a Victor.

[DonRotolo]

We have a DSC with PWM port 4 inoperative. Being busy we did not stop to diagnose it (other than to confirm it is dead), we purchased another, intending to return the first one to (somwehere) for repair.

Eric, I can arrange for it to be in Atlanta if you are interested.

[BJT]

we had a limit switch stop working and finally figured out that switching ports on the DSC fixed it.

[kgzak]

We had a problem were all our DIO's stopped working. We swapped out our DSC and they worked. We then bought a new DSC to make sure we had a backup for competition and opened up the DSC that broke and found a ton of metal shavings in it. We emptied it out and it worked fine. We now use that DSC for our testing CRIO.

[Al Skierkiewicz]

Don't overlook the multipin connector coming loose on the Sidecar. It may appear to be engaged but may only be touching a few contacts and show intermittent during match play while showing fine during tether in the pit.

[EricVanWyk]

Originally Posted by Don Rotolo

We have a DSC with PWM port 4 inoperative. Being busy we did not stop to diagnose it (other than to confirm it is dead), we purchased another, intending to return the first one to (somwehere) for repair.

Eric, I can arrange for it to be in Atlanta if you are interested.

Don -

That would be great, Thank You.

- Eric

[Tom Line]

Eric - check your PM's. I sent you my contact info - where should I send the part?

[mlim]

Interesting, we think we had a similar problem during our practice rounds where the motor would only run in one direction. As a rookie team we just used one DSC running two Jags controlling CIMs and two servos. We thought we had a terminal crimp problem, but after redoing 5-6 terminals we still had the problem. We were about to change out the DSC when I noticed a 1/4 inch metal shaving tangled in a pin area. Once we removed the shaving the motors worked. Makes me thing that we should mount the boards upside down to prevent the metal shavings falling into the components. I guess then all we have to worry is the connectors from falling out. I had seen a few teams mount their electronics vertically. Just a thought for next year.

[Lafleur]

We had a DS die on us, +5v led on, no VBATT led, no 6V led on.. (odd combination as VBATT is 12v and that's what drives the +5v and +6v switchers)

Opened up the unit and Q1, the reverse voltage FET was blown.. Well its was in many pieces... Removed it, the +6v switcher was again working and the VBATT led was back on... Ordered an new FET from Digikey and all is well...

Whats odd here is this unit was in our TEST robot, and the hardware configuration had not change in weeks, remove the bad unit, replaced it with a new unit and we were back in business... do not understand the root cause of the failure... it might just be a bad part!!

tom lafleur
mentor team 812
the Preuss school at UCSD