The compal-a5wahea50hblab991pr10.pdf document details the Compal LA-B991P motherboard used in Acer Aspire E5-571 and E5-531 laptops, featuring Intel Haswell/Broadwell ULT processors and optional NVIDIA discrete graphics. Troubleshooting for no-power conditions often involves inspecting the +3VALW rail or the KB9012 Embedded Controller for failure points. The full schematic and boardview files can be found on LaptopBlue or Scribd .