A Technical Field Guide for Diagnostics and Repair DOCUMENT OVERVIEW This guide provides an exclusive breakdown of the power-on sequence for modern desktop motherboards. Understanding this sequence is critical for diagnosing "no power" and "no post" issues. We break down the process into three distinct phases: Standby , Power On , and Runtime . 1. PHASE 1: STANDBY STATE (S5 State) Before the power button is pressed, the motherboard is never truly "off." It sits in the ACPI S5 (Soft Off) state, waiting for a wake-up signal. Course Sidekick Downloader - 3.79.94.248