Sidecar Assembly Problem

[dbarr4011]

We received our 2009 controls and over the weekend installed the controls onto our test robot. While unpacking and checking our kit of parts the Sidecar assembly had a small rattle. We opened the case and found capacitor C15 had come off the board and was loose in the enclosure. We also open the second Sidecar and also found C15 as pushed out of place. We found that the Sidecar enclosure has a plastic ridge that pushes the capacitor C15 out of place. We notched the plastic cover for both Sidecar assemblies and re-installed the loose and out of place C15 capacitor. WARNING - This is an extremely small surface mount part. Do not attempt to solder unless you have a surface mount rework station and have training working on surface mounted boards. Also the conformal coating around the capacitor needs to be cleaned before working on the board.

We were able to get our test robot running through the radio system and using the base vehicle code in about 3 hours.

David Barr
Team 141

[DarkOps_Developer]

We received our 2009 controls and over the weekend installed the controls onto our test robot. While unpacking and checking our kit of parts the Sidecar assembly had a small rattle. We opened the case and found capacitor C15 had come off the board and was loose in the enclosure. We also open the second Sidecar and also found C15 as pushed out of place. We found that the Sidecar enclosure has a plastic ridge that pushes the capacitor C15 out of place. We notched the plastic cover for both Sidecar assemblies and re-installed the loose and out of place C15 capacitor. WARNING - This is an extremely small surface mount part. Do not attempt to solder unless you have a surface mount rework station and have training working on surface mounted boards. Also the conformal coating around the capacitor needs to be cleaned before working on the board.

We were able to get our test robot running through the radio system and using the base vehicle code in about 3 hours.

David Barr
Team 141

David, thanks for the information. I opened a DSC here and was wondering if the numbering that you have on your pcb is different? C15 is over by the 37 pin connector with reasonable clearance from case moldings. I did see a potential interferance point in the center of the pcb with C6 and the case ridge that looks like a backwards capital L (looking at the opened case). Could this be the device you are referring to? C15 is near J12 while C6 is near C4 and the power inductor. Just wondering...

[jross]

I just opened one of our DSCs and found that C6 was tombstoned. It looks like it occurred after conformal coating, which would seem to confirm a mechanical issue.

See the attached picture.

[Charles Harris]

Same observation here, we have one digital side car with "something" loose inside.

Charles Harris, FRC 623

[dbarr4011]

I just opened one of our DSCs and found that C6 was tombstoned. It looks like it occurred after conformal coating, which would seem to confirm a mechanical issue.

See the attached picture.

You all are correct, I have the wrong part listed in my notes. Thanks for the update.

[kbaker159]

I checked ours as well, both are loose and the gooey stuff is holding them on. It looks like someone didn't check the clearances there. I'm going to notch both of ours and possibly repair them, but I don't know if they are integral. I know it worked without them in the default code, but maybe that doesn't use a feature that required it. Any idea what it is part of and If it is necessary to repair it? I would rather not spend the time with small tools if it isn't a really necessary repair.

[Russ Beavis]

Fortunately, it's a redundant filter capacitor for the switching power supply that provides 6V power for servos (you can rarely have too much capacitance!). We're working on it and should be able to provide an official response very soon.

Russ

[Kate]

It's confirmed. The C6 capacitor is essentially redundant and therefore unnecessary. The remaining C4 capacitor has sufficient specifications to provide filtering for the 6V servo power supply. It may provide a slight reduction in noise in the 6V servo power supply but we have been unable to detect any negative effects via testing at FIRST HQ.

Fortunately, the Digital Sidecar has conformal coat and, as a result, a loose C6 capacitor will NOT result in any electrical shorts within the module.

We do recommend that teams open the case and remove the loose component.