This page covers common issues with production boards not functioning correctly, and includes tips for debugging.  

Assembly Checks

Care needs to be taken at the assembly stage with the Topaz LGA. Open circuits between the LGA module and base-board will occur if care is not taken during the manufacturing process.  Review our guidelines with your assembly house to ensure a good yield.

Boot Resistors and Power

The most likely cause of a board not booting is a problem with the boot configuration resistors.  The can be either:

1. A missing resistor
2. A fitted resistor (that should be a no-fit)
3. The power rail for a resistor is not coming up to voltage fast enough at boot.  This is more of a design issue, but can manifest during early production.

Out of all of these, missing, or incorrectly fitted resistors is the biggest cause of board issues we have seen.

Power Supply issues

Should you need to probe the Topaz LGA module, we have included an image below highlighting where the key power rails and signals can be accessed.