This is a follow up to the entry about the electrical shorts in the printed circuit boards last week.

After a few days of “beating [his] head against the wall”, Brian Piquette from Synapse took both the working and non-working circuit boards back to the manufacturer to get them X-Rayed.

The X-Ray revealed solder bridges which caused the short circuits and the manufacturer was able to fix most of the boards in a few hours. The photos below show the solder bridges circled.

Most of the shorts were under the board-to-board connectors and it was determined that the problems were a result of a manufacturing problem, not a design problem.

The manufacturer is going to X-Ray all future boards before delivery to confirm that the manufacturing process is now turning out good boards.

We’ve hit a few challenges in the hardware project. Here is an e-mail that Brian, the Electrical Engineer on the Falstaff project sent to our internal mailing list yesterday:

Well…The build of 20 units has not gone as cleanly as I had hoped.

There has been pretty low yield on the two PCBs. Less than 50% on the Main board and ~75% on the Button board.

For the Main PCB there are a lot of boards that have processor bus data lines shorted to each other.

For example one of the boards looks to have D8 and D10 shorted together.

If you look at the layout of the board, you’ll see that D8 and D10 are adjacent to each other at the board to board connector and under the SDRAM BGA. See the image below.

If you look at the left side, you’ll see two pins on the connector that are colored yellow. These are D8 and D10.

I suspect that they are shorted either under the J2 connector or under the U7 BGA.

I’m taking 10 boards over to PCA to morrow to have them x-rayed to see if we can locate the shorts, then fix them.

The fallout on the Button board seems to be a bit more random. On one board, the Left Illumination LED doesn’t work, on another the SM Bus data line is shorted to ground.

That being said, I’ve give 7 working board sets to Dave to get assembled into units. We’ll work on getting more working and assembled ASAP…