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By: JohnBoucher
New: 07-02-2009 19:41
Updated: 07-02-2009 19:41
Views: 1135 times
Team 237 is on it's 3rd sidecar. We found a problem was found with the digital side car capacitor (C6) wave-flow process. We found that C6, which appear to be a capacitor connected to the relay contacts of L1, was not properly soldered to the printed wiring board surface mount solder pads. This problem was noted on all three digital side cars that we examined.
Two cards that we examined found that C6 was loose and floating around on the card, causing a possible short circuit on one card.
Capacitor C6 was loose due to cold solder joints on one card and when touched broke free and detached from the solder pads. A closer examination showed that the C6 solder pads were shorted together with solder with capacitor C6 sitting on top of the short.
Discussion
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08-02-2009 01:21
Eldarion
Re: pic: Sidecar problem
Technically that would be a solder reflow problem, not a wave-flow problem. 
Wave soldering is used to solder through-hole parts, whereas reflow soldering is used for surface-mount parts.
Looks like they may have a problem with their paste mask?
08-02-2009 04:08
Joe Ross
Re: pic: Sidecar problem
See http://forums.usfirst.org/showthread.php?t=10621
08-02-2009 08:15
Russ Beavis
Re: pic: Sidecar problem
I don't think that FIRST wants you to return your sidecars if that missing/loose capacitor is the only issue. The conformal coating on the board should keep any loose parts or metal filings (within reason) of causing any issues.
Did you have any other issues with the sidecar? Did it work fine otherwise?
Russ
08-02-2009 08:49
JohnBoucher
Re: pic: Sidecar problem
It appears to be the only issue. Is C6 necessary and does removing it affect anything?
08-02-2009 10:04
synth3tk
Re: pic: Sidecar problem
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Originally Posted by JohnBoucher
It appears to be the only issue. Is C6 necessary and does removing it affect anything?
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Originally Posted by 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. |
08-02-2009 12:31
falconmaster
Re: pic: Sidecar problem
Between two teams and ourselves we have 4 side cars that do not work. We were a beta test team and we are on our spare side car. We have made no wiring changes and the second car is working fine. The first side car worked fine for 4 weeks. We suspect a quality control or faulty design. We are going to buy two more because we are expecting them to go out. We are watching all the threads about this
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