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By: EricVanWyk
New: 17-03-2013 09:23
Updated: 17-03-2013 09:23
Views: 1698 times
A friendly reminder to protect your electronics from dust/shavings/etc!
A pair of power distribution boards was returned for failure analysis - both failed at competition in ways that severely affected the match outcome. In the unit pictured, the 12V boost regulator was not boosting, and instead passed battery voltage (minus a diode drop) to the radio. This "works" fine until the battery voltage sags and reboots the radio, taking the robot out of the match for many seconds.
When I opened the board I found many forms of swarf, including metal dust, wire clippings, wood shavings, hair, and onion skin. There were at least 3 candidate short circuits caused by swarf, though it is impossible to be certain which fault was active as they can move during shipping or during game play.
This is a rev 4 - the original shipped version. More recent versions have a protective conformal coating, which reduces but does not eliminate this problem. The other returned board was this year's version, and shows signs of swarf interference.
Discussion
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17-03-2013 18:46
Jared Russell
Re: pic: Swarf in Power Distribution Board
Note to self: Stop using our spare PDB as a cutting board.
20-03-2013 15:46
splatter
Re: pic: Swarf in Power Distribution Board
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Originally Posted by Jared341
Note to self: Stop using our spare PDB as a cutting board.
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20-03-2013 16:11
JesseK
Re: pic: Swarf in Power Distribution Board
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Originally Posted by Jared341
Note to self: Stop using our spare PDB as a cutting board.
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20-03-2013 16:38
EricVanWyk
Re: pic: Swarf in Power Distribution Board
Cutting board might make the "Top Ten PD Uses That Make Eric Cry", but it wouldn't make the top 5.
The lovely DiscoBots still owe me a stiff drink for using the poor thing as a spring/dashpot in their minibot deployer.
I've also seen "Machine Shop Door Stop"... and people wonder why fault modes tend to come in clusters...
20-03-2013 22:45
DonRotolo
Re: pic: Swarf in Power Distribution Board
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Originally Posted by EricVanWyk
Cutting board might make the "Top Ten PD Uses That Make Eric Cry",
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20-03-2013 23:14
juanfe92
Re: pic: Swarf in Power Distribution Board
I'm curious, has any body considered opening these boards up and conformal coating the inside? Has any team actually done it?
Edit: Nevermind, I re-read the original post. Sorry
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