| 1 | DC Input | Adapter / DC-IN main rail | Adapter/battery input path | Schematic p.7 | Follow chronological sequence | 19-20 V typical for barrel adapters; USB-C depends on PD contract | Measure to ground at input connector/fuse | Flat DC; inspect ripple only if unstable |
| 2 | DC Input | Input fuse - both sides | DC jack -> protection path | Schematic p.37 | Follow chronological sequence | Same voltage on both sides of input fuse | DMM DC at both fuse sides to ground; continuity with power removed | Flat DC |
| 3 | Charger | ACDET / adapter detect | Adapter divider -> charger IC | Schematic p.41 | Follow chronological sequence | IC-specific adapter-detect threshold; commonly about 2-3 V | DMM DC at ACDET | Flat DC |
| 4 | Charger | ACOK / AC_PRESENT | Charger -> EC/PCH | Schematic p.5 | Follow chronological sequence | Valid logic state when adapter accepted; commonly logic high | DMM logic level | Clean logic transition when adapter is inserted |
| 5 | Charger | REGN / charger internal LDO | Charger IC internal LDO | Schematic p.41 | Follow chronological sequence | IC-specific; often about 6 V on TI BQ families | DMM DC at REGN pin/cap | Flat DC |
| 6 | Charger | ACDRV / input MOSFET gate drive | Charger -> input MOSFET gates | Schematic p.41 | Follow chronological sequence | Gate drive above source when input path is enabled; exact value IC-specific | Measure gate and source; compare VGS | Gate should rise cleanly after valid adapter detect |
| 7 | Battery | Battery positive / system battery rail | Battery connector -> charger/system | Schematic p.7 | Follow chronological sequence | Pack voltage appropriate to cell count and state of charge | DMM DC at battery positive to pack ground | Flat DC; no excessive ripple |
| 8 | RTC | RTC / CMOS supply | RTC source -> PCH/SoC | Schematic p.7 | Follow chronological sequence | Typically near 3 V; board-specific | DMM DC | Flat DC |
| 9 | Always-On | 3 V always-on rail | Standby regulator -> EC/PCH/logic | Schematic p.6 | Follow chronological sequence | 3.3 V nominal where this rail exists | DMM DC at inductor/output cap | Flat DC with low ripple |
| 10 | Always-On | 5 V always-on rail | Standby regulator -> peripherals | Schematic p.9 | Follow chronological sequence | 5.0 V nominal where design provides always-on 5 V | DMM DC at inductor/output cap | Flat DC with low ripple |
| 11 | EC / SIO | EC / SIO supply | Standby rail -> EC/SIO | Schematic p.37 | Follow chronological sequence | Usually 3.3 V or design-specific auxiliary rail | DMM DC at EC decoupling capacitor | Flat DC |
| 12 | EC / SIO | EC reset | Reset circuit -> EC/SIO | Schematic p.5 | Follow chronological sequence | Released to inactive logic level after EC supply is valid | DMM logic level | Clean release edge; no repetitive reset cycling |
| 13 | EC / SIO | 32.768 kHz RTC / EC clock | Crystal/oscillator -> EC/PCH | Schematic p.5 | Follow chronological sequence | Stable 32.768 kHz where external low-frequency clock is used | DMM not reliable; use scope | Stable low-amplitude sine/square waveform near 32.768 kHz |
| 14 | Power State | RSMRST# | EC/PCH resume-well logic | Schematic p.5 | Follow chronological sequence | Inactive/high after resume-well prerequisites are satisfied | DMM logic level | Clean low-to-high transition during standby initialization |
| 15 | Power Sequence | SLP_S5# | PCH/SoC -> EC/power logic | Schematic p.5 | Follow chronological sequence | Deasserts/high when leaving S5; exact polarity/name platform-specific | DMM logic level | Step transition during power-on |
| 16 | Power Sequence | SLP_S3# | PCH/SoC -> EC/power logic | Schematic p.5 | Follow chronological sequence | Deasserts/high when entering S0 | DMM logic level | Step transition |
| 17 | Power Sequence | SUS_ON / MAINON | EC/power logic -> main regulators | Schematic p.9 | Follow chronological sequence | Active state enables main/S0 rails; polarity board-specific | DMM logic level | Clean enable transition |
| 18 | Memory | DDR VDD / VDDQ | Memory regulator -> DIMM/SoC | Schematic p.9 | Follow chronological sequence | DDR generation-specific rail; verify schematic and memory generation | DMM DC at memory inductor | Flat DC; low ripple |
| 19 | CPU / SoC | CPU core rail | CPU VR -> processor core | Schematic p.7 | Follow chronological sequence | VID-controlled dynamic voltage; do not use a single universal value | DMM DC at core inductor | Multiphase switching on switch nodes; DC on output |
| 20 | Reset | PLTRST# | PCH/SoC -> platform devices | Schematic p.34 | Follow chronological sequence | Released/inactive after clocks and power-good conditions are satisfied | DMM logic level | Clean low-to-high release |
| 21 | BIOS / SPI | SPI_CS# | PCH/SoC/EC -> SPI flash | Schematic p.6 | Follow chronological sequence | Idle high with access pulses during firmware reads | DMM not diagnostic; use scope | Chip-select pulse bursts during start-up |
| 22 | BIOS / SPI | SPI_CLK | PCH/SoC/EC -> SPI flash | Schematic p.5 | Follow chronological sequence | Clock bursts during firmware access | DMM not diagnostic; use scope | High-frequency clock bursts |
| 23 | Display | eDP HPD | Panel -> GPU/PCH/SoC | Schematic p.4 | Follow chronological sequence | Valid HPD logic state when panel is connected and powered | DMM logic level | Clean logic level/transition |
| 24 | USB-C / PD | USB-C VBUS | USB-C port -> system power path | Schematic p.32 | Follow chronological sequence | 5 V default; 9/15/20 V or other profiles after valid PD contract | DMM DC | Flat negotiated DC; scope for transients only |