It all started back in December of 2009, when chumby was in the midst of production for the chumby One. A call came in from the floor noting that SMT yield had dropped dramatically on one lot, so I drove over to the building to have a look (this is the advantage of being in China during production — you can fix problems like this within the hour, before they become really serious issues). After poking and prodding a bit, I realized that all the units failing had Kingston microSD cards from a particular lot code. I had the factory pull the entire lot of microSD cards from the line and rework all the units that had these cards loaded. Sure enough, after subtracting these cards from the line, yield was back to normal again.
Normally, the story would end there; you’d RMA the material, get an exchange for the lot, and move on. Except there were a couple of problems. First, Kingston wouldn’t take the cards back because we had programmed them. Second, there was a lot of them — about a thousand all together, and chumby was already deeply back-ordered. Also, memory cards aren’t cheap; the spot price on this type of memory card is around $4-5, so it’s a few thousand dollars in scrap if we can’t get them exchanged … and neither chumby nor the CM is large enough to sneeze at a few kilobucks.
So I kicked into forensic mode....
