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MarcFinns / AtmoScan

Interactive air multisensor
https://www.youtube.com/watch?v=iyFuKU8ZcuA
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VBat conductor shorted to ground on PCB #14

Open schofiel opened 7 months ago

schofiel commented 7 months ago

The VBat conductor between the Sparkfun TOL 10617 battery positive pin and the BAT/BAT 2 inputs to the MAX8903A charge management IC U2 (pins 21 & 20) is shorted to ground on the PCB by a flood-filled polygon zone. This is on the top copper layer. The design rule checker does not mark the intersection of the polygon with the track as a problem.

The net result is that U2 (MAX8903A) fails to regulate properly and the board fails to operate (dead short/no voltage). With the battery pack connected, the pack delivers peak current (3x 5A) to ground, with the associated fire risk due to battery failure.

An image of the polygon:

VBat Polygon

An image of the resulting top copper gerber:

VBat Polygon on Gerber

The work-around is a careful scalpel cut along the edge of the track to separate the polygon from ground.

schofiel commented 7 months ago

Should note that this is for the V2 board version.